Conformal Silicon Oxide Deposition for High-Aspect Ratio Features
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Solution Overview
Problem
Current deposition techniques struggle to produce high-quality conformal silicon oxide (SiOx) films on high aspect ratio semiconductor structures, particularly in reentrant features like GAA and 3D DRAM, due to limited chemical precursors with robust thermal stability, high reactivity, and vapor pressure, leading to contamination and poor film quality.
Innovation Solution
A method involving a semiconductor processing chamber that exposes a substrate to a silicon-containing precursor, purge gases, and a remote plasma source microwave plasma to deposit conformal silicon oxide films, minimizing gas phase reactions and ion bombardment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional CVD or PECVD techniques are used to deposit silicon oxide films, then film deposition can occur, but the films exhibit high wet etch rates and poor conformality on high aspect ratio structures
Solution Approach 1:
The patent changes the fundamental deposition parameters by switching from plasma-enhanced or thermal CVD to atomic layer deposition (ALD) methodology. This involves using sequential pulsed exposures of silicon-containing precursor and oxidizing agent precursors, with purge steps between each exposure, thereby achieving atomic-layer-controlled conformal deposition with superior film quality and low wet etch rates that cannot be achieved by conventional CVD or PECVD
Solution Approach 2:
The patent introduces a remote plasma source as an intermediary mechanism to activate the precursors. The remote plasma source generates reactive species that enhance the reactivity of the precursors during ALD cycles, enabling high-quality film deposition at lower temperatures without the harmful effects of direct plasma exposure, thus resolving the contradiction between conformality and film quality
2Productivity
If halogen-containing silane precursors are used for atomic layer deposition of silicon oxide, then film deposition can occur, but halogen contamination affects device performance and requires additional removal procedures
Solution Approach 1:
The patent extracts and eliminates the harmful halogen component from the precursor chemistry. By selecting silicon-containing precursors that do not contain halogen atoms (such as silane derivatives with organic ligands), the method removes the source of halogen contamination entirely, allowing high-productivity deposition without introducing harmful contaminants that would require additional removal steps
Solution Approach 2:
The patent employs precursors with labile, easily removable organic ligands that decompose during or after deposition, leaving clean silicon oxide films. These transient organic groups serve as temporary carriers that deliver silicon to the substrate and then decompose, enabling high deposition rates without persistent contamination
3Object-generated harmful factors
If high temperature processes are used to remove halogen contamination, then halogen removal can be achieved, but temperature-sensitive substrates are damaged
Solution Approach 1:
The patent converts the potential harm of using temperature-sensitive substrates into a benefit by developing a deposition methodology that operates at low temperatures. By using precursors with inherently low decomposition temperatures and a remote plasma activation approach, the method achieves effective halogen-free deposition at temperatures that protect temperature-sensitive device structures, turning the substrate's thermal sensitivity into an advantage for selective low-temperature processing
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 achieves high-quality, conformal silicon oxide films with low wet etch rates and desirable electrical properties, suitable for high aspect ratio structures without damaging surrounding semiconductor structures.
Implementation Method 1
exposing the semiconductor substrate to a remote plasma source (RPS) microwave plasma to deposit a conformal silicon oxide (SiOx) film on a surface of the semiconductor substrate
Implementation Method 2
exposing the semiconductor substrate to a remote plasma source (RPS) microwave plasma
Data Source
AI summary
Methods of depositing high-quality conformal silicon oxide (SiOx) films in the formation of semiconductor devices are described. The methods include exposing a semiconductor substrate to a first precursor, a first purge gas, a second precursor, a second purge gas, and a remote plasma source (RPS) microwave plasma to deposit a conformal silicon oxide (SiOx) film.