Selective SAM Film Formation on Oxide-Treated Metal Surfaces
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Solution Overview
Problem
Existing film forming methods struggle to selectively and uniformly form self-assembled monolayers (SAMs) on substrates with non-uniform natural oxide films, leading to inconsistent film quality and selectivity.
Innovation Solution
A film forming method that involves reducing the natural oxide film on a substrate, forming a uniform metal oxide film, and then selectively forming a SAM on the conductive film using a thiol-based organic compound, while inhibiting SAM formation on insulating films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a self-assembled monolayer is formed directly on a substrate with natural oxide film, then the formation process is simple, but the film uniformity and selectivity are poor
Solution Approach 1:
The patent applies preliminary action by performing reduction and oxidation treatments on the substrate surface before forming the self-assembled monolayer. The natural oxide film is first reduced to expose fresh metal surfaces, then selectively oxidized to create uniform metal oxide regions that promote consistent SAM formation. This preliminary preparation resolves the contradiction by establishing a controlled surface state that enables both uniform film formation and process feasibility.
Solution Approach 2:
The patent utilizes parameter changes by controlling the oxidation state of the substrate surface through sequential reduction and oxidation steps. By adjusting the oxidation conditions, uniform metal oxide films are created on conductive regions while insulating regions remain unaffected. This parameter control enables selective and uniform SAM formation, resolving the contradiction between process simplicity and film uniformity.
2Manufacturing precision
If photolithography is used to form patterns before SAM formation, then area selectivity is achieved, but the process complexity increases
Solution Approach 1:
The patent extracts the pattern definition step from the traditional photolithography process by utilizing the inherent material properties of conductive and insulating films. The selective oxidation treatment automatically patterns the substrate surface based on the underlying conductive/insulating film distribution, eliminating the need for separate photolithography steps while maintaining area selectivity.
Solution Approach 2:
The substrate surface performs self-patterning through selective oxidation. The conductive regions automatically form metal oxide layers that promote SAM formation, while insulating regions do not. This self-service mechanism achieves area selectivity without requiring external photolithography equipment or complex process steps.
3Productivity
If the natural oxide film is not reduced, then the process steps are minimized, but the SAM formation selectivity and uniformity deteriorate
Solution Approach 1:
The reduction step serves as a preliminary action that removes the natural oxide film to expose fresh metal surfaces. This creates a uniform starting state that enables subsequent selective oxidation and consistent SAM formation. The preliminary reduction resolves the contradiction by establishing conditions that simultaneously improve selectivity and maintain process efficiency.
Solution Approach 2:
The patent changes the oxidation state parameter of the substrate surface through reduction followed by selective oxidation. This parameter transformation creates distinct surface states on conductive versus insulating regions, enabling selective SAM formation. The parameter change approach resolves the contradiction between process efficiency and formation selectivity.
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 achieves selective and uniform formation of SAMs in desired areas, improving film quality and selectivity, and enabling efficient semiconductor manufacturing processes.
Implementation Method 1
a reducing gas is supplied into the process container so as to remove a natural oxide film from a surface of the substrate
Implementation Method 2
an oxidizing gas is supplied into the process container so as to form a metal oxide film on the surface of the conductive film
Implementation Method 3
a self-assembled monolayer is formed on the surface of the conductive film by supplying a raw material gas of the self-assembled monolayer
Data Source
AI summary
A film forming method for forming an object film on a substrate including: providing the substrate including an oxide layer of a first material formed on a layer of the first material formed on a surface of a first area, and a layer of a second material formed on a surface of a second area, the second material being different from the first material; reducing the oxide layer; oxidizing a surface of the layer of the first material after reducing the oxide layer; and forming a self-assembled monolayer on the surface of the layer of the first material by supplying a raw material gas of the self-assembled monolayer after oxidizing the surface of the layer of the first material.