Self-Assembled Monolayer Formation for Selective ALD Nucleation Blocking
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Solution Overview
Problem
Current semiconductor processing techniques face challenges in selectively preventing unwanted film deposition on reactor surfaces and device structures during atomic layer deposition (ALD) and chemical vapor deposition (CVD) processes, leading to contamination and increased processing time due to non-selective film buildup on exposed surfaces.
Innovation Solution
A method involving the formation of a self-assembled monolayer (SAM) on exposed surfaces using a two-step process with intermediate cooling of the substrate, where a first SAM precursor is adsorbed followed by a second precursor to create a dense, pin-hole-free SAM that resists nucleation and allows selective deposition on adjacent surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a self-assembled monolayer is formed using a single-step vapor phase process, then the process is simpler and faster, but the resulting SAM has pin-holes and poor density leading to non-selective deposition
Solution Approach 1:
The single-step SAM formation process is divided into multiple sequential steps: first forming an initial SAM layer, then cooling the substrate, and finally forming a supplemented SAM layer. This segmentation allows each step to optimize for its specific function, achieving both speed and quality.
Solution Approach 2:
The first SAM layer is formed as a preliminary protective layer before the supplemented layer. This preliminary action creates a foundation that, when combined with the cooling step and second precursor exposure, results in a dense, pin-hole-free final SAM structure.
2Device complexity
If deposition is performed without selective surface treatment, then the process is simpler, but unwanted film buildup occurs on reactor surfaces and dielectric areas causing contamination and requiring additional patterning steps
Solution Approach 1:
The SAM formation process creates different surface properties in different locations. By exposing only specific surfaces to the SAM precursors and controlling the deposition conditions, a protective monolayer is formed selectively on desired surfaces while leaving other surfaces untreated and reactive for subsequent deposition.
Solution Approach 2:
The SAM layer is formed in advance as a protective barrier that prevents unwanted film deposition on specific surfaces during subsequent processing steps. This preliminary protective action eliminates the need for additional patterning and etch steps to remove unwanted material.
3Productivity
If reactor surfaces are exposed during multiple substrate processing, then throughput is improved, but film buildup on reactor surfaces increases total surface area requiring longer pulse and purge times
Solution Approach 1:
The process changes the surface energy parameters of reactor surfaces by forming a SAM layer with different chemical composition and surface properties. This parameter change reduces the reactivity of reactor surfaces with deposition precursors, minimizing film buildup and reducing the time required for pulse and purge cycles.
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 process effectively reduces unwanted film deposition on reactor surfaces and device structures, enhancing the selectivity and efficiency of subsequent deposition processes by creating a SAM with improved water contact angles and preventing film growth on undesired areas.
Implementation Method 1
supplying a first self-assembled monolayer (SAM) precursor to adsorb an initial SAM over an exposed surface of the substrate
Implementation Method 2
cooling the substrate with the initial SAM
Implementation Method 3
supplying a second SAM precursor to the initial SAM after the cooling to produce a supplemented SAM over the exposed surface of the substrate
Data Source
AI summary
The present application discloses forming self-assembled monolayers (SAMs) by exposing the substrate at least twice to SAM precursors with intervening cooling of a substrate.