Resist Composition for KrF Lithography Standing Wave Suppression
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Solution Overview
Problem
The negative type pattern forming method using organic solvent development suffers from significant standing waves, poor rectangularity, and increased development defects, particularly in KrF exposure, without the need for an antireflection film, and struggles with forming fine trench patterns and high line edge roughness.
Innovation Solution
A pattern forming method utilizing an actinic ray-sensitive or radiation-sensitive resin composition containing a resin with specific repeating units such as naphthyl, biphenyl, and anthryl groups, combined with a compound having a naphthalene ring, which absorbs exposure light, allowing for development without an antireflection film, and using a developer with organic solvents to achieve high rectangularity and reduced defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If negative type pattern forming method using organic solvent development is employed, then fine trench patterns can be formed, but standing waves occur and pattern rectangularity deteriorates
Solution Approach 1:
The patent introduces a specific resin composition as an intermediary layer between the substrate and the resist pattern. This resin composition, containing aromatic groups and acid-decomposable units, acts as a mediator that absorbs excess light energy and prevents standing wave formation, thereby maintaining pattern rectangularity while enabling fine trench formation
Solution Approach 2:
The patent changes the chemical composition parameters of the resin by incorporating specific aromatic groups (naphthyl, biphenyl, anthryl, fluorenone, anthrone, xanthone, thioxanthone, vinyl benzene, or diphenyl sulfone structures) and acid-decomposable units. This compositional change modifies the light absorption characteristics and solubility properties, reducing standing waves and improving pattern shape
2Object-affected harmful factors
If antireflection film is provided to reduce standing waves, then standing waves are reduced, but manufacturing cost increases due to additional etching step
Solution Approach 1:
The patent extracts and eliminates the need for a separate antireflection film by incorporating the antireflection functionality directly into the resin composition. The aromatic groups in the resin serve the dual purpose of structural component and standing wave suppressor, removing the harmful reflection effect without adding process complexity
Solution Approach 2:
The resin composition is designed to perform multiple functions simultaneously: it serves as the structural base material, the light-absorbing layer for standing wave reduction, and the development medium. This multi-functionality eliminates the need for separate antireflection film and its associated etching process
3Use of energy by moving object
If conventional resist composition is used for KrF exposure, then sensitivity is maintained, but development defects increase due to poor film peeling property
Solution Approach 1:
The patent creates a composite resin system combining aromatic group-containing polymers with acid-decomposable units. This composite structure provides both the light sensitivity required for KrF exposure and the controlled peeling properties needed for defect-free development, resolving the contradiction between sensitivity and reliability
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 method effectively inhibits standing waves, enhances exposure latitude and line edge roughness, and reduces development defects, enabling the formation of high-quality, fine trench patterns without the need for an antireflection film, particularly in KrF exposure.
Implementation Method 1
by exposure such as an excimer laser, electron beams, extreme ultraviolet light, or the like, an acid generator is decomposed at exposed portions to generate an acid
Implementation Method 2
the generated acid is used as a reaction catalyst in a post exposure bake (PEB: Post Exposure Bake) to convert an alkali-insoluble group into an alkali-soluble group
Implementation Method 3
developing the exposed film using a developer including an organic solvent to form a negative tone pattern
Implementation Method 4
an image forming method in which, by exposure such as an excimer laser, electron beams, extreme ultraviolet light, or the like, an acid generator is decomposed at exposed portions to generate an acid
Data Source
AI summary
A pattern forming method including: (i) forming a film using an actinic ray-sensitive or radiation-sensitive resin composition containing a resin (A) having a repeating unit having a group generating a polar group upon being decomposed by the action of an acid, and a repeating unit having an aromatic group, a compound (B) generating an acid upon irradiation with actinic rays or radiation, and a solvent (C); (ii) exposing the film; and (iii) developing the exposed film using a developer including an organic solvent to form a negative tone pattern, wherein the resin (A) is a resin having a repeating unit having a naphthyl group, and the like, and/or the actinic ray-sensitive or radiation-sensitive resin composition contains a compound (D) having a naphthalene ring, and the like.