Halogenated Silane Nucleation Layer Thickness Control
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Solution Overview
Problem
Existing methods for depositing metal silicides using silane-based atomic layer deposition exhibit high growth per cycle and poor thickness control, particularly on structures with high aspect ratios, leading to inadequate control over film thickness and step coverage.
Innovation Solution
A method involving sequential exposure of a substrate to a metal precursor and a halogenated silane in a processing chamber, with specific process regions and gas curtains to form a nucleation layer of tungsten or molybdenum silicide with precise thickness control, followed by bulk metal film deposition using WF6 or MoF6 and hydrogen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If silane-based atomic layer deposition is used to deposit metal silicides, then the deposition rate is high (GPC > 5 Å/cycle), but the thickness control is poor and step coverage is low on high aspect ratio structures
Solution Approach 1:
The patent changes the chemical parameters of the deposition process by replacing standard silane (SiH4) with halogenated silanes such as SiCl4, SiBr4, or SiI4. This parameter change in the co-reactant chemistry fundamentally alters the reaction kinetics and surface chemistry, enabling both high deposition rates and precise thickness control. The halogenated silanes provide more controlled surface reactions compared to conventional silane, resolving the contradiction between productivity and manufacturing precision.
2Productivity
If silane-based atomic layer deposition is used to deposit metal silicides, then the deposition rate is high (GPC > 5 Å/cycle), but the step coverage on structures with high aspect ratios is low
Solution Approach 1:
By changing the chemical parameters to use halogenated silanes, the surface reaction characteristics are improved. The halogenated silanes provide better surface diffusion and more uniform reaction kinetics that enable excellent step coverage on high aspect ratio structures while maintaining high deposition rates, thus resolving the contradiction between productivity and shape quality.
3Quantity of substance
If conventional metal precursor and silane deposition is used, then the growth per cycle is high, but the control over film thickness is poor
Solution Approach 1:
The patent applies parameter changes by substituting conventional silane with halogenated silane co-reactants. This chemical parameter change results in more predictable and controllable surface reactions, allowing precise control of film thickness while maintaining appropriate growth rates. The halogenated silanes provide better reaction stoichiometry and surface coverage control, resolving the contradiction between quantity of substance deposited and manufacturing precision of film thickness.
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 achieves improved growth per cycle control and step coverage, allowing for the formation of nucleation layers with thickness in the range of 5 Å to 100 Å at a controlled rate of 0.1 Å/cycle to 10 Å/cycle, enhancing the precision of metal film deposition.
Implementation Method 1
The substrate surface is sequentially exposed to a first reactive gas and a second reactive gas to form a nucleation layer on the surface. The first reactive gas comprises a metal precursor and the second reactive gas comprises a halogenated silane.
Implementation Method 2
A metal film is bulk deposited on the nucleation layer by repeating sequential exposure of the nucleation layer to a third reactive gas and a fourth reactive gas to form a bulk metal film of a predetermined thickness.
Data Source
AI summary
Methods for forming a nucleation layer on a substrate. In some embodiments, the processing method comprises sequential exposure to a first reactive gas comprising a metal precursor and a second reactive gas comprising a halogenated silane to form a nucleation layer on the surface of the substrate.