Semiconductor Chamber Conditioning for Selective Titanium Nitride Etching
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Solution Overview
Problem
Conventional etching processes face challenges in achieving high selectivity and uniformity, particularly in removing titanium nitride relative to other materials, and often suffer from residual fluorine radicals adhering to chamber walls, which affect subsequent etch processes and substrate uniformity.
Innovation Solution
The method involves forming conditioning plasma effluents using oxygen-containing and fluorine-containing precursors to treat the interior surfaces of a semiconductor processing chamber, followed by etching with remote plasma effluents through a showerhead, maintaining specific temperature and pressure conditions to ensure selective etching of titanium nitride with high selectivity relative to tungsten and uniformity across the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If local plasma is used for etching, then trench penetration and structure preservation are improved, but substrate damage from electric arcs and plasma effluents worsens
Solution Approach 1:
A showerhead is introduced as an intermediary component between the plasma source and substrate. The showerhead distributes plasma effluents uniformly across the substrate surface, preventing direct concentration of harmful electric arcs at specific points while maintaining the beneficial etching effects. This mediator structure allows the system to achieve both precise trench etching and reduced substrate damage.
2Manufacturing precision
If wet HF etch is used, then selectivity for silicon oxide removal is improved, but penetration into constrained trenches and deformation control worsen
Solution Approach 1:
The patent replaces wet chemical etching (liquid-based) with plasma-based etching (gas-phase reactive species). This substitution allows the etchant to reach into constrained trenches through gas-phase diffusion and reactive ion bombardment, overcoming the penetration limitations of liquid wet etchants while maintaining material selectivity through controlled plasma chemistry.
3Productivity
If plasma power is increased to improve etching rate, then productivity is improved, but substrate damage from electric arcs worsens
Solution Approach 1:
The system dynamically controls plasma parameters including power delivery, gas flow rates, and pressure conditions to optimize the balance between etching rate and substrate damage. By adjusting these dynamic parameters, the process achieves high productivity while preventing harmful electric arc formation through controlled plasma stability.
Solution Approach 2:
The showerhead acts as a mediator that distributes plasma effluents uniformly, preventing concentration of high-energy ions and electrons at specific substrate points. This uniform distribution allows higher overall plasma power to be applied for increased etching rate while the showerhead structure prevents localized electric arc damage.
4Productivity
If fluorine-containing precursors are used for etching, then etching capability is improved, but residual fluorine radicals adhering to chamber walls worsen subsequent process stability
Solution Approach 1:
The system continuously conditions the chamber by maintaining a controlled plasma environment that prevents fluorine radical accumulation on chamber walls. Through continuous plasma generation and controlled effluent flow, the system keeps chamber surfaces in a stable state, ensuring consistent etching performance across multiple substrates without degradation from residual fluorine contamination.
Solution Approach 2:
The showerhead serves as an intermediary that controls the interaction between fluorine-containing plasma effluents and chamber walls. By directing and distributing the plasma flow, the showerhead prevents direct contact between high concentrations of fluorine radicals and chamber surfaces, reducing adhesion while maintaining effective etching on the substrate.
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 enhances etch process uniformity and stability by oxidizing and removing residual fluorine radicals, achieving selective etching of titanium nitride with a selectivity greater than 100:1 relative to tungsten and maintaining uniformity between edge and central regions of the substrate to within 5%.
Implementation Method 1
forming conditioning plasma effluents of an oxygen-containing precursor... treating the interior surfaces of the semiconductor processing chamber
Implementation Method 2
forming conditioning plasma effluents... in a semiconductor processing chamber
Implementation Method 3
flowing a fluorine-containing precursor into a remote plasma region... while forming a remote plasma... to produce etching plasma effluents... etching the exposed region of titanium nitride
Implementation Method 4
etching the exposed region of titanium nitride... with a selectivity relative to tungsten of greater than or about 100:1
Implementation Method 5
forming a remote plasma in the remote plasma region to produce etching plasma effluents... flowing the etching plasma effluents into the substrate processing region through apertures in a showerhead
Implementation Method 6
A temperature of the substrate may be maintained between about 200° C. and about 500° C. during the etching
Data Source
AI summary
Exemplary methods for conditioning a processing region of a semiconductor processing chamber may include forming conditioning plasma effluents of an oxygen-containing precursor in a semiconductor processing chamber. The methods may include contacting interior surfaces of the semiconductor processing chamber bordering a substrate processing region with the conditioning plasma effluents. The methods may also include treating the interior surfaces of the semiconductor processing chamber.