Doped Silicon Nitride Film Deposition for Low-Temperature Conformality
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Solution Overview
Problem
Existing methods for depositing doped silicon nitride layers face challenges in achieving conformality and desired dopant concentrations, particularly for high aspect ratio features, and often require high temperatures or plasma processes that can damage the layers.
Innovation Solution
A method involving thermal cyclic deposition processes using different precursors and reactants in sequential cycles to form doped silicon nitride films, allowing for conformal deposition and dopant tuning at low temperatures without plasma, utilizing halogenated silane compounds and nitrogen-containing gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If plasma-enhanced chemical vapor deposition (PECVD) is used to deposit doped silicon nitride layers at relatively low temperatures, then the deposition temperature is reduced, but conformality and uniformity of the deposited layer deteriorate
Solution Approach 1:
The deposition process is divided into multiple sequential cycles, where each cycle deposits a thin layer. By segmenting the overall deposition into many small cycles with precursor and reactant pulses, the process achieves both low temperature operation and conformal coverage of high aspect ratio features.
Solution Approach 2:
The patent employs periodic pulsing of precursor and reactant gases in alternating cycles. This periodic action allows controlled deposition at each cycle, ensuring uniform conformal layers while maintaining low processing temperatures, thereby resolving the contradiction between temperature reduction and conformality maintenance.
2Temperature
If plasma is used during deposition, then deposition can occur at relatively low temperatures, but damage to the deposited layer or underlying layer occurs
Solution Approach 1:
The patent extracts and eliminates the plasma component from the deposition process, using purely thermal chemical vapor deposition instead. This removes the harmful plasma effects that could damage sensitive layers while maintaining the ability to deposit at relatively low temperatures through controlled thermal cycles.
Solution Approach 2:
The patent uses transient precursor molecules that decompose and react during each deposition cycle, leaving no residual harmful plasma effects. These short-living precursor species enable low-temperature deposition without the damaging persistent effects of plasma.
3Manufacturing precision
If thermal deposition techniques are used to conformally deposit quality doped silicon nitride layers, then conformality is improved, but deposition temperature becomes relatively high and undesirably high
Solution Approach 1:
The patent introduces dynamic temperature control through cyclic heating and cooling during deposition. The substrate temperature is dynamically adjusted in sync with precursor and reactant pulsing, allowing conformal deposition at lower average temperatures than traditional continuous thermal CVD processes.
Solution Approach 2:
The patent changes the temperature parameter from a constant high value to a dynamically varying lower value through cyclic pulses. By modulating temperature in conjunction with precursor/reactant pulsing, the process achieves conformal deposition at reduced temperatures, resolving the contradiction between conformality and temperature.
4Manufacturing precision
If thermal cyclic deposition processes are used with different precursors and reactants, then dopant concentration control is improved, but process complexity increases
Solution Approach 1:
The patent employs a universal cyclic deposition platform that can deposit both silicon nitride and doped silicon nitride using the same equipment and process framework. By using different precursor combinations in the same cyclic process, the system achieves precise dopant control without requiring separate complex deposition systems.
Solution Approach 2:
The patent controls dopant concentration by changing chemical parameters (precursor selection and ratios) rather than requiring complex physical parameter adjustments. This approach achieves precise dopant control through relatively simple compositional changes within the cyclic process, minimizing the increase in overall process complexity.
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 method enables conformal doped silicon nitride films with controlled dopant concentrations and improved properties, such as low dielectric constant and etch resistance, suitable for semiconductor applications.
Implementation Method 1
using a first thermal cyclic deposition process, forming a layer comprising silicon nitride, and using a second thermal cyclic deposition process, forming a layer comprising doped silicon nitride
Data Source
AI summary
A method of forming a doped silicon nitride film on a surface of a substrate and structures including the doped silicon nitride film are disclosed. Exemplary methods include forming a layer comprising silicon nitride using a first thermal process and forming a layer comprising doped silicon nitride using a second thermal process to thereby form the doped silicon nitride film.