Carbon Gapfill Deposition for Void-Free High-Aspect-Ratio Trenches
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Solution Overview
Problem
Conventional carbon gapfill processes struggle to uniformly fill gaps between high aspect ratio features in semiconductor devices with high-quality carbon material layers without leaving voids, due to issues like overhang formation and undesired oxidization.
Innovation Solution
The use of plasma enhanced CVD (PECVD) or flowable CVD (FCVD) processes to deposit high-quality, stable carbon films, involving selective deposition, pulsed bias plasma treatment to densify the carbon material, and selective etching to remove material overhangs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If carbon material is deposited at the top and along sidewalls of a trench, then the trench filling is improved, but overhangs are created that pinch off the trench and result in voids
Solution Approach 1:
The patent applies preliminary action by performing a preliminary carbon deposition step before the main gapfill deposition. This preliminary layer is deposited at lower pressure and lower rate, creating a foundation that prevents overhang formation during subsequent high-rate deposition. The preliminary action prepares the surface and structural conditions to avoid the pinchoff problem that would otherwise occur.
Solution Approach 2:
The patent implements periodic action by alternating between deposition steps and etch steps in a cyclic manner. The process includes: (1) depositing carbon material, (2) etching overhangs, (3) depositing more carbon, (4) etching again, and repeating this cycle until the trench is fully filled. This periodic alternation prevents permanent pinchoff by removing overhangs before they can seal off the trench, while still achieving complete filling over time.
2Productivity
If conventional CVD processes are used to deposit carbon, then deposition speed is improved, but film quality and stability deteriorate due to void formation
Solution Approach 1:
The patent applies preliminary action by performing a preliminary carbon deposition step before the main gapfill deposition. This preliminary layer is deposited at lower pressure and lower rate, creating a foundation that prevents overhang formation during subsequent high-rate deposition. The preliminary action prepares the surface and structural conditions to avoid the pinchoff problem that would otherwise occur.
Solution Approach 2:
The patent implements periodic action by alternating between deposition steps and etch steps in a cyclic manner. The process includes: (1) depositing carbon material, (2) etching overhangs, (3) depositing more carbon, (4) etching again, and repeating this cycle until the trench is fully filled. This periodic alternation prevents permanent pinchoff by removing overhangs before they can seal off the trench, while still achieving complete filling over time.
3Manufacturing precision
If carbon deposition is performed to fill gaps, then gapfilling is improved, but undesired oxidization occurs affecting device performance
Solution Approach 1:
The patent applies the inert atmosphere principle by conducting the carbon deposition process in a controlled atmosphere that prevents oxidization. The process uses inert or reducing ambient conditions during deposition and includes protective measures during handling and processing. This inert environment protection ensures the carbon material remains stable and does not undergo undesired oxidization that would degrade device performance.
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 enables the formation of high-quality carbon gapfill structures that effectively address the challenges of void formation and structural flaws in conventional methods, ensuring improved device performance and processing efficiency.
Implementation Method 1
selectively depositing a film onto a structure of a semiconductor substrate disposed in a processing region of a semiconductor processing chamber, the film comprising a carbon material
Implementation Method 2
exposing the semiconductor substrate to pulsed bias plasma treatment to selectively densify the carbon material of the film deposited at a bottom of the structure
Implementation Method 3
selectively etching the film from a sidewall of the structure
Implementation Method 4
depositing a flowable film onto a structure of a semiconductor substrate disposed in the processing region with plasma effluents of the carbon-containing precursor
Data Source
AI summary
The present disclosure provides methods and apparatus that facilitate the formation of high-quality carbon gapfill structures and that address the issues related to conventional carbon gapfill methods. In certain embodiments, the carbon gapfill methods and apparatus described herein include plasma enhanced CVD (PECVD) or flowable CVD (FCVD) processes to gapfill structures with high-quality, and stable carbon films.