SiOCN Layer Deposition with Controlled Nitrogen and High Etch Resistance
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Solution Overview
Problem
Existing methods for forming silicon oxycarbonitride (SiOCN) layers face challenges such as low growth rate and difficulty in controlling nitrogen content, which affects etch resistance and dielectric constants, particularly when using nitrogen-containing reactants in plasma-enhanced chemical vapor deposition (PECVD) processes.
Innovation Solution
A method involving the formation of SiOC and SiCN layers using distinct silicon precursors and reactants, where the first reactant does not include nitrogen and the second reactant does not include oxygen, to create a silicon oxycarbonitride layer with improved properties through a cyclical deposition process in a reactor, allowing for controlled composition and enhanced film characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If nitrogen-containing reactants are used in PECVD to form SiOCN layers, then the layers can be deposited at relatively low temperatures, but the growth rate is relatively low and nitrogen content is difficult to control
Solution Approach 1:
The patent segments the deposition process into two separate sequential steps: first depositing a SiOC layer using a silicon precursor and carbon-containing reactant, then depositing a SiCN layer using a different silicon precursor and nitrogen-containing reactant. This segmentation allows independent optimization of each layer's composition and growth conditions, achieving both high growth rate and precise nitrogen content control in the final SiOCN layer.
Solution Approach 2:
The patent employs dynamic adjustment of process parameters including alternating between different silicon precursors (e.g., silane and tetraethyl orthosilicate), varying reactant flows (O2, N2, H2O), and adjusting plasma power levels during deposition. This dynamic control enables real-time optimization of growth rate and composition, resolving the contradiction between productivity and manufacturing precision.
2Reliability
If nitrogen-containing reactants are used to form SiOCN layers, then the layers exhibit desired etch resistance and dielectric constants, but the growth rate is limited by nitrogen groups forming on the substrate surface
Solution Approach 1:
The patent performs preliminary deposition of a SiOC layer before depositing the SiCN layer. This preliminary SiOC layer serves as a foundation that prevents excessive nitrogen group accumulation on the substrate surface, thereby maintaining high growth rate while still achieving the desired etch resistance and dielectric constants in the final SiOCN layer.
Solution Approach 2:
The patent creates a composite structure by combining SiOC and SiCN layers in a sequential deposition process. The SiOC layer provides a stable base with good etch resistance, while the SiCN layer adds nitrogen content for tuning dielectric constants. This composite approach achieves the desired reliability properties without sacrificing growth rate.
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 wet etch resistance, low dielectric constant, and reduced leakage current, making it suitable for various applications like 3D cross-point memory devices and DRAM storage node contact isolation, with tunable carbon and nitrogen concentrations.
Implementation Method 1
Plasma-enhanced chemical vapor deposition (PECVD) can be used to deposit silicon oxycarbonitride layers on a substrate surface at relatively low temperatures
Implementation Method 2
Plasma-enhanced chemical vapor deposition (PECVD) can be used to deposit silicon oxycarbonitride layers on a substrate surface
Data Source
AI summary
A method of forming a silicon oxycarbonitride layer on a substrate is disclosed. An exemplary method includes forming a layer comprising SiOC and forming a layer comprising SiCN, which together form the silicon oxycarbonitride layer.