Conformal Silicon Oxide Multi-Layers for Reduced Pattern Loading
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Solution Overview
Problem
Current methods for depositing dielectric layers on patterned substrates face challenges in achieving conformal deposition, leading to surface defects and non-uniform film thickness, particularly in semiconductor device fabrication, where high temperature processes are becoming less viable due to shrinking device geometry.
Innovation Solution
The method involves depositing conformal silicon oxide multi-layers by sequentially flowing BIS(DIETHYLAMINO)SILANE (BDEAS) and oxygen-containing precursors in a processing chamber, with optional plasma treatment to enhance conformality and reduce wet etch rates, allowing for uniform deposition across densely and sparsely patterned regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high temperature, low pressure conventional CVD is used to deposit silicon oxide layers, then step coverage is improved, but thermal budget becomes too high for shrinking device geometry
Solution Approach 1:
The patent changes the deposition parameters from high temperature conventional CVD to low temperature PECVD, using plasma enhancement to achieve adequate step coverage at reduced thermal budgets suitable for modern semiconductor device geometry
Solution Approach 2:
The patent replaces the thermal field (high temperature CVD) with a plasma field (PECVD) to achieve the same deposition function at lower temperatures, using electromagnetic energy to activate the chemical reactions
2Temperature
If PECVD processes are used to deposit silicon oxide at lower temperatures, then thermal budget is reduced, but step coverage and pattern loading results are not as desirable
Solution Approach 1:
The patent employs multi-cycle deposition processes with alternating precursor flows and plasma on/off cycles to build up conformal layers with improved step coverage, using periodic reinforcement to overcome the limitations of single-step PECVD
Solution Approach 2:
The patent divides the deposition process into multiple cycles with sub-layers, where each cycle deposits a portion of the total thickness, allowing cumulative improvement in conformality and step coverage that single-step processes cannot achieve
3Manufacturing precision
If conformal deposition is attempted over patterned features, then uniform thickness is desired, but surface defects and non-uniform film thickness occur due to overloafing
Solution Approach 1:
The patent uses multiple deposition cycles that deposit slightly more than the final required thickness in each cycle, then selectively remove material through etching to achieve the precise target thickness with improved uniformity, using iterative approximation to overcome single-step limitations
Solution Approach 2:
The patent implements process control that monitors deposition characteristics and adjusts subsequent cycle parameters to compensate for variations, using feedback from previous cycle results to optimize the next deposition step for improved conformality
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 a conformal silicon oxide multi-layer with reduced pattern-loading effects, improved step coverage, and lower wet etch rates, making it suitable for non-sacrificial applications and enabling the use of the films in finished semiconductor devices.
Implementation Method 1
performing a first cycle of chemical vapor deposition comprising the operations: flowing BDEAS into the substrate processing region, flowing a first oxygen-containing precursor into the substrate processing region, and forming a first conformal silicon oxide sub-layer of the conformal silicon oxide multi-layer on the patterned substrate from the BDEAS and the oxygen-containing precursor by chemical vapor deposition
Implementation Method 2
A plasma treatment may follow formation of sub-layers to further improve conformality and to decrease the wet etch rate of the conformal silicon oxide multi-layer film
Data Source
AI summary
Aspects of the disclosure pertain to methods of depositing conformal silicon oxide multi-layers on patterned substrates. The conformal silicon oxide multi-layers are each formed by depositing multiple sub-layers. Sub-layers are deposited by flowing BIS(DIETHYLAMINO)SILANE (BDEAS) and an oxygen-containing precursor into a processing chamber such that a relatively uniform dielectric growth rate is achieved across the patterned substrate surface. A plasma treatment may follow formation of sub-layers to further improve conformality and to decrease the wet etch rate of the conformal silicon oxide multi-layer film. The deposition of conformal silicon oxide multi-layers grown according to embodiments have a reduced dependence on pattern density while still being suitable for non-sacrificial applications.