Crosslinkable Overcoat Multipatterning for Sub-Resolution Spacers
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Solution Overview
Problem
Existing semiconductor fabrication methods face challenges in achieving sub-lithographic patterning without the use of advanced exposure systems or gas phase inorganic films, which are costly and complex.
Innovation Solution
The use of crosslinkable and reversible overcoat materials that undergo acid-catalyzed reactions to form spacers or antispacers, allowing for the formation of sub-resolution features through acid diffusion from photoresist mandrels, eliminating the need for slow inorganic depositions and hardmask transfers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If advanced exposure systems or gas phase inorganic films are used for sub-lithographic patterning, then manufacturing precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces complex gas phase inorganic film deposition processes with a simpler spin-on organic overcoat material process. The organic material undergoes acid-catalyzed crosslinking reactions after exposure, eliminating the need for sophisticated inorganic deposition equipment and complex hardmask transfer steps, thereby reducing device complexity while achieving sub-lithographic patterning precision
Solution Approach 2:
The patent changes the material state and chemical properties by using crosslinking reactions in the organic overcoat material. The crosslinking density and reaction conditions are controlled to achieve precise pattern formation, enabling sub-lithographic critical dimensions through chemical parameter control rather than complex physical deposition processes
2Manufacturing precision
If gas phase inorganic films and hardmask transfers are used, then manufacturing precision is improved, but productivity decreases due to slow deposition processes
Solution Approach 1:
The patent substitutes slow gas phase inorganic deposition with rapid spin-on coating of organic materials. The spin-on process is inherently faster than sequential inorganic deposition and hardmask transfer steps, significantly improving productivity while maintaining patterning precision through controlled acid diffusion and crosslinking reactions
Solution Approach 2:
The patent performs preliminary crosslinking of the organic overcoat material during or after exposure, creating a stable pattern structure in advance. This eliminates the need for subsequent hardmask transfer steps, reducing the total number of process steps and improving overall fabrication speed while preserving pattern fidelity
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
Enables finer critical dimensions and line edge roughness control without altering photoresist formulations, reducing complexity and cost by using spin-on materials for multipatterning.
Implementation Method 1
exposing the substrate to an ultraviolet (UV) irradiation to generate acid in the plurality of mandrels
Implementation Method 2
The diffused acid may induce a crosslinking reaction in the portion to form a crosslinked portion of the overcoat material
Implementation Method 3
diffusing the acid into a portion of the overcoat material
Data Source
AI summary
An example method of processing a substrate includes patterning a photoresist deposited over the substrate to form a plurality of mandrels, and spin coating an overcoat material over the plurality of mandrels. The method includes exposing the substrate to an ultraviolet (UV) irradiation to generate acid in the plurality of mandrels; diffusing the acid into a portion of the overcoat material. The diffused acid induces a crosslinking reaction in the portion to form a crosslinked portion of the overcoat material. The method includes performing a developing process using a developing solution to remove the plurality of mandrels and the overcoat material except the crosslinked portion of the overcoat material.