Amorphous Carbon Film Deposition for Conformal High-Aspect Structures
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Solution Overview
Problem
Conventional methods for depositing carbon-based films, such as PECVD and PVD, face challenges in achieving conformality, which limits their usefulness in semiconductor applications, particularly for high aspect ratio structures and back-end-of-line barrier layers.
Innovation Solution
The method employs molecular layer deposition (MLD) processes using sequential self-limiting surface reactions with carbon precursors like 1,4-phenylene diisocyanate and ethylene diamine to form carbon polymer films, followed by plasma treatment and thermal annealing to enhance conformality and thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If PECVD or PVD processes are used to deposit carbon-based films, then high quality films can be formed, but conformality is poor especially on high aspect ratio structures
Solution Approach 1:
The deposition process is segmented into sequential half-cycles, where each half-cycle deposits a thin layer from one precursor, followed by purification, then the next precursor is introduced. This segmentation allows each layer to form uniformly before the next is added, improving conformality on high aspect ratio structures while maintaining film quality through controlled reaction conditions.
Solution Approach 2:
The process uses periodic introduction of precursors and purging cycles, alternating between depositing layers from different carbon precursors. This periodic action ensures uniform coverage by allowing complete reaction and purification between each deposition event, resolving the contradiction between conformality and film quality.
2Productivity
If conventional PECVD processes are used for carbon film deposition, then deposition speed is relatively high, but film conformality deteriorates
Solution Approach 1:
The fast deposition is achieved by segmenting the process into multiple rapid half-cycles that can be executed sequentially. Each half-cycle deposits a thin conformal layer quickly, and by stacking multiple such cycles, high overall deposition speed is achieved while maintaining conformality at each step through the segmented approach.
Solution Approach 2:
The substrate is prepared with specific surface treatments and the process conditions are pre-optimized before each deposition cycle to enable rapid yet conformal deposition. This preliminary preparation allows the subsequent fast deposition to maintain both speed and conformality without compromising film quality.
3Adaptability or versatility
If carbon films are deposited for high aspect ratio structures, then application requirements are met, but conventional processes cannot achieve sufficient conformality
Solution Approach 1:
The segmented deposition approach allows the film to be built up layer-by-layer, with each thin layer conformally covering the high aspect ratio structures. This incremental segmentation enables penetration into deep features while maintaining uniform thickness, making the process adaptable to high aspect ratio applications with superior conformality.
Solution Approach 2:
The process parameters including temperature, pressure, and precursor flow rates are optimized for each half-cycle to enhance penetration into high aspect ratio structures. By adjusting these parameters sequentially across multiple cycles, the process achieves both the adaptability needed for complex structures and the conformality required for uniform coverage.
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 results in conformal carbon-based films with improved thermal stability up to 400°C, suitable for high aspect ratio structures, and tunable carbon, hydrogen, and oxygen ratios, addressing the limitations of conventional deposition methods.
Implementation Method 1
exposing a substrate to a first carbon precursor to form a first precursor terminated surface on the substrate
Implementation Method 2
The first precursor terminated surface is exposed to a second carbon precursor to form a carbon polymer film on the substrate
Implementation Method 3
a configuration to expose the carbon polymer film on a substrate to a plasma treatment
Implementation Method 4
a configuration to anneal the carbon polymer film
Data Source
AI summary
Methods of forming carbon polymer films are disclosed. Some methods are advantageously performed at lower temperatures. The substrate is exposed to a first carbon precursor to form a substrate surface with terminations based on the reactive functional groups of the first carbon precursor and exposed to a second carbon precursor to react with the surface terminations and form a carbon polymer film. Processing tools and non-transitory memories to perform the process are also disclosed.