Selective Titanium CVD Using Remote Plasma for Silicon Contacts
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Solution Overview
Problem
Existing selective deposition processes for titanium and titanium silicides face challenges in achieving high selectivity between silicon and dielectrics like silicon nitride and silicon oxide, leading to non-uniformity and limited feature fill in high aspect ratio features, which affects contact resistance and fill volume.
Innovation Solution
A method involving remote plasma reactions between titanium tetrachloride, hydrogen, and argon at controlled temperatures, combined with direct plasma reactions, is used to selectively deposit titanium materials on silicon surfaces while inhibiting deposition on dielectric surfaces, enhanced by pretreatment with silane and post-treatment with silane and hydrogen radicals to improve selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional selective deposition processes are used, then titanium material can be deposited on silicon surfaces, but deposition also occurs on dielectric surfaces (sidewalls and bottom of features), resulting in poor selectivity
Solution Approach 1:
The patent changes the chemical parameters of the deposition process by using titanium tetrachloride (TiCl4) as the titanium source instead of conventional titanium precursors. By controlling the plasma power, pressure, and temperature parameters, the process achieves high selectivity (>40:1) for silicon surfaces over dielectric surfaces, preventing unwanted deposition on sidewalls and bottoms of high aspect ratio features
Solution Approach 2:
The patent introduces plasma as an intermediary medium to enable selective deposition. The plasma activates the titanium tetrachloride precursor and facilitates selective reaction on silicon surfaces while inhibiting deposition on dielectric surfaces. The plasma parameters (power, frequency, composition) are controlled to achieve the desired selectivity
2Quantity of substance
If deposition occurs on dielectric sidewalls to fill features, then feature fill volume is limited, but contact resistance increases and uniformity is reduced
Solution Approach 1:
By changing the deposition parameters (plasma power, pressure, gas composition, temperature) and using titanium tetrachloride as precursor, the process achieves high selectivity that allows complete filling of high aspect ratio features with metallic material while preventing deposition on dielectric sidewalls, thereby maximizing fill volume and maintaining uniformity
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 selective deposition of titanium materials with a selectivity ratio greater than 40:1 towards silicon, reducing contact resistance and maximizing feature fill volume, and minimizes deposition on dielectric sidewalls, resulting in uniform substrates.
Implementation Method 1
forming a remote plasma reaction between titanium tetrachloride (TiCl4), hydrogen (H2) and argon (Ar) in a region between a lid heater and a showerhead of a process chamber at a first temperature of 200 to 800 degrees C.; and flowing reaction products into the process chamber to selectively form a titanium material layer upon the silicon surface
Implementation Method 2
forming a remote plasma reaction between titanium tetrachloride (TiCl4), hydrogen (H2) and argon (Ar) within a process chamber between a lid heater and a showerhead to form a titanium material layer upon a substrate inside the process chamber to selectively deposit the titanium material layer atop the silicon surface
Data Source
AI summary
Methods and apparatus for selectively depositing a titanium material layer atop a substrate having a silicon surface and a dielectric surface are disclosed. In embodiments an apparatus is configured for forming a remote plasma reaction between titanium tetrachloride (TiCl4), hydrogen (H2) and argon (Ar) in a region between a lid heater and a showerhead of a process chamber at a first temperature of 200 to 800 degrees C.; and flowing reaction products into the process chamber to selectively form a titanium material layer upon the silicon surface of the substrate.