Selective Deposition Using Multi-Solvent Self-Assembled Monolayer
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Solution Overview
Problem
The existing selective deposition methods for forming semiconductor structures face challenges in achieving precise control over the deposition of material layers on metal and low-k dielectric portions, often resulting in poor selectivity and coverage due to the use of unsuitable solvents and solubility issues with blocking compounds.
Innovation Solution
A multi-solvent system comprising propylene glycol monomethyl ether (PGME) and propylene glycol monomethyl ether acetate (PGMEA) is used to prepare a self-assembled monolayer (SAM) solution, which includes a blocking compound with a specific chemical structure, allowing for selective deposition of a material layer on one portion while preventing deposition on the other, using the blocking layer as a stencil without the need for lithography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single solvent is used to prepare the blocking compound solution, then the process is simple, but the selectivity and coverage of the blocking layer are poor
Solution Approach 1:
The patent uses a composite solvent system comprising propylene glycol monomethyl ether (PGME) and propylene glycol monomethyl ether acetate (PGMEA) instead of a single solvent. This composite solvent system provides both good solubility for the blocking compound and appropriate volatility characteristics, resulting in improved selectivity and coverage of the blocking layer while maintaining process simplicity.
2Manufacturing precision
If a blocking layer is formed to prevent material deposition, then selectivity is improved, but the metal portion resistance may be affected
Solution Approach 1:
The patent carefully controls the parameters of the solvent system (PGME and PGMEA ratio, volatility characteristics) to optimize the blocking layer formation. The blocking compound is applied in a controlled manner and then removed, ensuring that the blocking layer provides sufficient deposition selectivity while not adversely affecting the metal portion resistance. The specific solvent composition allows for precise control of the blocking layer properties.
3Manufacturing precision
If lithography is used to define deposition areas, then precision is achieved, but the process complexity and cost increase
Solution Approach 1:
The patent extracts and eliminates the lithography step from the conventional deposition process. Instead of using lithography to define deposition areas, the invention uses a chemically selective blocking layer that naturally prevents material deposition on specific areas (metal or low-k dielectric portions) based on the chemical affinity of the blocking compound for the underlying surface. This simplifies the process while maintaining precision.
Solution Approach 2:
The blocking layer acts as an intermediary between the deposition process and the underlying substrate. The blocking compound selectively adheres to either metal or low-k dielectric surfaces, creating a chemical barrier that directs material deposition without requiring physical lithography patterns. This intermediary layer provides the necessary selectivity while eliminating complex lithography steps.
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 the selectivity and coverage of the blocking layer, ensuring that the material layer is deposited only on the intended surface, maintaining the resistance of the metal portion and providing sufficient protection to the low-k dielectric layer, while being environmentally friendly and scalable.
Implementation Method 1
a self-assembled monolayer (SAM) solution, which includes a blocking compound with a specific chemical structure, allowing for selective deposition of a material layer on one portion while preventing deposition on the other
Implementation Method 2
the substrate is heated to remove the multi-solvent system of the SAM solution over the surfaces of the metal portion and the low-k dielectric portion
Data Source
AI summary
A method for forming a semiconductor structure is provided. A substrate including a metal portion and a low-k dielectric portion formed thereon is provided. The metal portion adjoins the low-k dielectric portion. A SAM solution is prepared. The SAM solution includes at least one blocking compound and a multi-solvent system. The multi-solvent system includes an alcohol and an ester. The SAM solution is applied over surfaces of the metal portion and the low-k dielectric portion. The substrate is heated to remove the multi-solvent system of the SAM solution to form a blocking layer on one of the metal portion and the low-k dielectric portion. A material layer is selectively deposited on the other one of the metal portion and the low-k dielectric portion using the blocking layer as a stencil. The blocking layer is removed from the substrate.