Reversible Overcoat Composition for Sub-Lithographic Wafer Patterning
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Solution Overview
Problem
Conventional photolithography processes face limitations in achieving symmetrical sub-lithographic critical dimensions and pitch resolution, particularly in creating features with opposite tone from deposited materials, leading to complex and costly processes.
Innovation Solution
The use of monomer and polymer compositions with crosslinking and de-crosslinking structures enables reversible overcoat layers for anti-spacer patterning, allowing for the formation of both trenches and lines through a single composition that can crosslink and de-crosslink, overcoming pitch limitations and achieving symmetrical sub-lithographic mandrel patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional photolithography processes are used to create symmetrical sub-lithographic features, then pitch resolution is limited, but process complexity and cost increase
Solution Approach 1:
The patent changes the chemical parameters of the overcoat layer by incorporating monomers with specific functional groups (crosslinkable groups, acid-cleavable groups) that enable the material to undergo chemical transformations in response to processing conditions, achieving sub-lithographic pitch resolution through controlled chemical reactions rather than physical process complexity
Solution Approach 2:
The patent uses composite monomer compositions containing multiple functional components (polymerizable units, crosslinking structures, acid-cleavable structures) that work together to enable both crosslinking and de-crosslinking behaviors, allowing the overcoat layer to function as a reversible patternable material that simplifies the overall patterning process
2Adaptability or versatility
If additional post-exposure processes are added to create trenches and lines, then patterning capabilities improve, but throughput decreases
Solution Approach 1:
The patent makes the overcoat layer universally patternable by incorporating both crosslinkable and acid-cleavable functional groups within the same material system, enabling the layer to be patterned into either trenches or lines (or both) through a single exposure and development process, eliminating the need for separate post-exposure processing steps and thereby maintaining high throughput while expanding patterning capabilities
3Strength
If overcoat layers are made insoluble through crosslinking, then etch resistance improves, but reversibility for pattern removal is lost
Solution Approach 1:
The patent creates a dynamic overcoat layer system where the crosslinking density and solubility characteristics can be reversibly changed in response to chemical stimuli (acid diffusion). The layer can transition from a soluble state to a crosslinked insoluble state for etch resistance, and then back to a soluble state for pattern removal, enabling both high etch resistance and complete reversibility through the incorporation of acid-cleavable crosslinking structures
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 approach enhances patterning capabilities by enabling the formation of symmetrical sub-lithographic features with improved throughput and reduced complexity, facilitating the creation of narrow trenches and lines without the need for additional post-exposure processes.
Implementation Method 1
a polymerizable unit, which includes an olefin
Implementation Method 2
a thermally or photochemically activatable crosslinking structure
Implementation Method 3
diffusing a portion of the plurality of acid particles from the plurality of first mandrels into portions of the crosslinked overcoat layer
Implementation Method 4
an acid-cleavable de-crosslinking structure
Data Source
AI summary
A composition for patterning substrates includes a monomer. The monomer includes a polymerizable unit, a thermally or photochemically activatable crosslinking structure, and an acid-cleavable de-crosslinking structure. The polymerizable unit includes an olefin.