Selective Gap Filling for High-Aspect-Ratio Oxide Trenches
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Solution Overview
Problem
Existing deposition processes struggle to efficiently fill high aspect ratio gaps or trenches in semiconductor devices due to limitations in void-free filling, especially as wiring pitch miniaturizes.
Innovation Solution
A method involving sequential plasma treatments and selective material deposition, where a substrate is subjected to a nitrogen-containing plasma followed by a noble gas plasma, allowing for the inhibition of the upper surface while enabling bottom-up growth of materials like silicon oxide in the gap features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional deposition processes are used to fill high aspect ratio gaps, then the deposition process can be simple and fast, but void-free filling cannot be achieved
Solution Approach 1:
The patent applies preliminary action by performing plasma treatments on the upper surface of the gap before deposition to inhibit material formation at the top. This pre-conditioning of the surface enables subsequent selective deposition to proceed without voids, resolving the contradiction between achieving void-free filling and maintaining deposition efficiency.
Solution Approach 2:
The patent implements local quality by creating spatially selective deposition conditions within the gap structure. The upper surface is chemically modified to be non-reactive to precursor gases, while the lower surface remains reactive, enabling material to deposit only at the bottom and grow upward without forming voids, thus achieving both precision and productivity.
2Manufacturing precision
If plasma treatments are applied to inhibit the upper surface, then selective bottom-up deposition can be achieved, but the process complexity increases
Solution Approach 1:
The patent applies parameter changes by modifying the chemical state of the upper surface through controlled plasma exposure. By changing the surface chemistry parameters (creating plasma-resistant surface groups), the process achieves selective deposition without requiring complex mask structures or multiple deposition chambers, thus managing complexity while maintaining precision.
3Manufacturing precision
If material is deposited to fill high aspect ratio gaps, then gap filling is achieved, but oxidation of silicon fins may occur
Solution Approach 1:
The patent employs inert atmosphere principles by using nitrogen-containing plasma and controlling the deposition environment to prevent oxidation. The plasma treatment creates a protective surface condition and the controlled atmosphere during deposition prevents oxygen from reaching and oxidizing the silicon fins, thus enabling gap filling while avoiding harmful oxidation side effects.
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 effectively fills high aspect ratio gaps with seamless silicon oxide, reducing leakage currents and improving resilience to chemical mechanical polishing, while maintaining low carbon and nitrogen content in the films, and avoiding oxidation of silicon fins.
Implementation Method 1
The substrate is subjected to a first plasma treatment. The substrate is then subjected to a second plasma treatment
Implementation Method 2
exposing the substrate to a precursor, thereby forming chemisorbed precursor on the lower surface
Implementation Method 3
exposing the substrate to an oxygen plasma, thereby allowing one or more oxygen-containing reactive species comprised in the plasma to react with the chemisorbed precursor on the lower surface, thereby forming an oxide on the lower surface
Data Source
AI summary
Methods and related systems for filling a gap feature comprised in a substrate are disclosed. The methods comprise a step of providing a substrate comprising one or more gap features into a reaction chamber. The one or more gap features comprise an upper part comprising an upper surface and a lower part comprising a lower surface. The methods further comprise a step of subjecting the substrate to a first plasma treatment and subjecting the substrate to a second plasma treatment. Thus the upper surface is inhibited while leaving the lower surface substantially unaffected. Then, the methods comprise a step of selectively depositing a material on the lower surface.