Selective Dielectric ALD Using SAM-Blocked Metal Surfaces
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Solution Overview
Problem
Current semiconductor manufacturing processes face challenges in selectively depositing silicon and oxygen-containing films like silicon oxide and carbon doped silicon oxynitride on dielectric surfaces without oxidizing metal or metal hydride layers, particularly using non-halogenated precursors and mild oxidants.
Innovation Solution
A thermal atomic layer deposition method is employed, using self-assembled monolayers to anchor organic thiol compounds on metal surfaces, while introducing tetraisocyanatosilane or related silicon compounds and an oxygen source, with a Lewis base catalyst, to selectively deposit silicon and oxygen-containing films on dielectric surfaces, avoiding metal surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional deposition methods using halogenated precursors or strong oxidants are used, then silicon and oxygen-containing films can be deposited, but metal or metal hydride layers are oxidized
Solution Approach 1:
The patent uses self-assembled monolayers (SAMs) as intermediary protective layers on metal surfaces. These SAMs selectively prevent the deposition of silicon and oxygen-containing films on metal substrates while allowing deposition on dielectric substrates. The SAMs act as a mediator that blocks harmful oxidation reactions on metal surfaces while enabling selective film formation on dielectric surfaces through surface chemistry differences.
Solution Approach 2:
The patent applies different surface treatments to different substrates within the same deposition chamber. Metal substrates are treated with self-assembled monolayers to create a protective barrier, while dielectric substrates receive no such treatment. This local differentiation of surface properties enables selective deposition - films form on dielectric surfaces but are blocked on metal surfaces, achieving high selectivity without cross-contamination or oxidation of metal layers.
2Object-affected harmful factors
If non-halogenated precursors and mild oxidants are used, then oxidation of metal layers is minimized, but deposition efficiency and film quality may be compromised
Solution Approach 1:
The self-assembled monolayers serve as an intermediary that enables the use of mild oxidants without compromising deposition efficiency. By providing a protective barrier on metal surfaces, the SAMs allow mild oxidants to be used safely, while the controlled reaction environment they create actually enhances film quality on dielectric surfaces through more uniform and manageable reaction kinetics.
Solution Approach 2:
The patent changes the chemical parameters of the deposition process by using non-halogenated precursors and mild oxidants instead of conventional aggressive chemicals. Combined with the SAM protective layers, this parameter change maintains or even improves deposition efficiency through better control of reaction conditions, while simultaneously preventing metal layer oxidation.
3Manufacturing precision
If self-assembled monolayers are introduced to protect metal surfaces, then selectivity is improved, but process complexity increases
Solution Approach 1:
The self-assembled monolayers are formed in advance of the deposition process through a preliminary surface treatment step. This preliminary action prepares the metal surfaces with protective layers before the main deposition occurs, enabling selective film formation without requiring complex real-time control mechanisms during deposition. The SAM formation is a simple, self-organizing process that reduces rather than adds to overall process complexity.
Solution Approach 2:
The self-assembled monolayers form through a self-organizing process where molecules automatically arrange themselves on metal surfaces without requiring complex external control. This self-service mechanism creates the protective barrier through spontaneous surface chemistry, eliminating the need for sophisticated equipment or complex process control systems to achieve selective deposition.
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 achieves selective deposition of silicon oxide, silicon oxynitride, and carbon doped films with low etch rates and tunable properties, ensuring minimal oxidation of metal surfaces and high purity, suitable for semiconductor applications.
Implementation Method 1
introducing at least one self-assembled monolayer (SAM) volatile precursor selected from the group consisting of organic thiol compounds to anchor on the metal surface more abundantly than on the dielectric surface
Implementation Method 2
introducing a silicon compound selected from the group consisting of tetraisocyanatosilane (TICS), triisocyanatosilane, and triisocyanatomethylsilane... to deposit the silicon compound on the dielectric surface
Implementation Method 3
reacting the adsorbed precursor and a reactant gas on the surface... to form a dielectric film having at least Si—C bonds on the substrate
Implementation Method 4
heating the reactor to at least one temperature ranging from ambient temperature to about 350° C.
Data Source
AI summary
A thermal atomic layer deposition method for selectively deposition of silicon and oxygen containing dielectric film selected from silicon oxide or carbon doped silicon oxide abundantly on a dielectric surface but not less on a metal surface employing a silicon precursor having at least three isocyanato ligands.