SiN Film Deposition Using Alternating NH and SiCl Surface Termination
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Solution Overview
Problem
Existing semiconductor manufacturing processes face challenges in achieving uniform film thickness of silicon nitride (SiN) films on substrates, leading to inconsistent film quality and processing resistance.
Innovation Solution
A method involving sequential supply of NH3 and SiCl4 gases to form alternating layers with SiCl and NH terminations, performed in cycles under controlled conditions to prevent gas-phase decomposition of SiCl4, ensuring uniform adsorptive substitution reactions and self-limiting Si adsorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional SiN film formation processes are used, then film formation is achieved, but film thickness uniformity in the substrate plane deteriorates
Solution Approach 1:
The film formation process is divided into multiple sequential half-cycles, each forming a thin layer (0.1-1 nm) with controlled termination. By segmenting the deposition into discrete steps with alternating SiCl4 and NH3 exposure, the process achieves atomic-layer precision and uniform thickness control across the substrate plane.
Solution Approach 2:
The substrate surface is pre-treated with NH3 to form NH termination before SiCl4 deposition. This preliminary action ensures uniform reactive sites across the substrate surface, enabling consistent adsorptive substitution reactions and uniform film nucleation in subsequent cycles.
2Length of moving object
If SiCl4 supply time is extended to improve film thickness, then film thickness increases, but gas-phase decomposition occurs
Solution Approach 1:
The process uses periodic alternation between SiCl4 supply (first half-cycle) and NH3 supply (second half-cycle) to build up film thickness incrementally. Each half-cycle is timed to deposit only 0.1-1 nm, preventing gas-phase decomposition while achieving cumulative thickness control through multiple cycles.
Solution Approach 2:
The process changes the deposition mechanism from gas-phase decomposition to surface adsorption by controlling temperature and timing parameters. By maintaining temperatures below gas-phase decomposition thresholds and using adsorptive substitution reactions, the process achieves film growth without harmful side reactions.
3Productivity
If multiple reactants are supplied simultaneously to form SiN film, then film formation speed increases, but film thickness uniformity deteriorates
Solution Approach 1:
The simultaneous supply of multiple reactants is segmented into sequential half-cycles with single reactant exposure. SiCl4 is supplied alone in the first half-cycle to form SiCl termination, followed by NH3 supply in the second half-cycle to form NH termination. This segmentation prevents gas-phase reactions while maintaining controlled deposition rates.
Solution Approach 2:
The process maintains continuous film formation through back-to-back half-cycles without idle time. Each half-cycle deposits a thin layer and terminates the surface for the next reaction, ensuring continuous useful action while preserving uniformity through sequential rather than simultaneous reactant supply.
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 SiN films with enhanced in-plane thickness uniformity and improved processing resistance, allowing precise control over film thickness and reducing gas costs by optimizing reactant supply times.
Implementation Method 1
forming NH termination on a surface of a substrate by supplying a first reactant containing N and H to the substrate
Implementation Method 2
forming a first SiN layer having SiCl termination formed on its surface by supplying SiCl4 as a precursor to the substrate to react the NH termination formed on the surface of the substrate with the SiCl4
Implementation Method 3
forming a second SiN layer having NH termination formed on its surface by supplying a second reactant containing N and H to the substrate to react the SiCl termination formed on the surface of the first SiN layer with the second reactant
Implementation Method 4
forming a first SiN layer having SiCl termination formed on its surface by supplying SiCl4 as a precursor to the substrate
Data Source
AI summary
There is provided a technique, including: (a) forming NH termination on a surface of a substrate by supplying a first reactant containing N and H to the substrate; (b) forming a first SiN layer having SiCl termination formed on its surface by supplying SiCl4 as a precursor to the substrate to react the NH termination formed on the surface of the substrate with the SiCl4; (c) forming a second SiN layer having NH termination formed on its surface by supplying a second reactant containing N and H to the substrate to react the SiCl termination formed on the surface of the first SiN layer with the second reactant; and (d) forming a SiN film on the substrate by performing a cycle a predetermined number of times under a condition where the SiCl4 is not gas-phase decomposed after performing (a), the cycle including non-simultaneously performing (b) and (c).