Pulsed CVD Titanium Nitride Via Interconnect Deposition
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Solution Overview
Problem
Current methods for manufacturing through-silicon vias face challenges in achieving compliant and contamination-free deposits, particularly in high form factor holes, leading to increased costs and reliability issues due to excess material removal and contamination risks.
Innovation Solution
A method involving pulsed chemical vapor deposition of titanium or tantalum nitride followed by copper deposition in separate chambers, with sequential and out-of-phase precursor and reactive gas injection, enhances compliance and reduces contamination, allowing for faster and more reliable layer formation without excess material deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If Atomic Layer Deposition (ALD) is used to deposit titanium or tantalum nitride, then compliance of the deposited layer is improved, but deposition time increases significantly and cost increases
Solution Approach 1:
The patent employs periodic pulsed deposition cycles where precursor gas and reactive gas are alternately introduced into the deposition chamber. Each cycle consists of a precursor pulse followed by a reactive gas pulse, creating periodic action that enables ALD-like compliance without requiring multiple sequential depositions. This periodic approach maintains the self-limiting surface reaction mechanism of ALD while reducing total deposition time.
Solution Approach 2:
The patent achieves continuous deposition by overlapping precursor and reactive gas pulses in a coordinated manner. The reactive gas pulse begins before the precursor pulse ends, ensuring continuous surface reaction without interruption. This continuity maintains high deposition rates while preserving layer compliance through controlled surface reactions.
2Productivity
If Physical Vapour Deposition (PVD) is used to deposit titanium or tantalum nitride, then deposition speed increases and cost decreases, but compliance of the deposited layer deteriorates
Solution Approach 1:
The patent replaces the physical vapor deposition mechanism (sputtering or evaporation) with a chemical vapor deposition mechanism using pulsed precursor and reactive gas introduction. This substitution transitions from a physical process that deposits material conformally but slowly to a chemical process that enables faster deposition while maintaining compliance through surface-limited reactions.
Solution Approach 2:
The patent changes the deposition parameters by controlling temperature, pressure, and gas flow rates to optimize the pulsed CVD process. By adjusting these parameters, the process achieves deposition rates comparable to PVD while maintaining the compliance benefits of chemical reaction-controlled deposition. The substrate temperature and gas pulse durations are specifically tuned to balance speed and quality.
3Manufacturing precision
If Chemical Vapour Deposition (CVD) is used to deposit titanium or tantalum nitride, then compliance improves compared to PVD, but contamination is introduced that reduces layer quality
Solution Approach 1:
The patent extracts and removes carbon-containing species from the deposition chamber between precursor and reactive gas pulses. The chamber is purged of excess precursor gas that could decompose and contaminate the layer. This extraction of harmful carbon species prevents contamination while maintaining the compliance benefits of CVD deposition.
Solution Approach 2:
The patent converts the potential harm of carbon-containing precursors into a benefit by using their reactivity to form the desired nitride layer. The precursor gas reacts with nitrogen to form titanium or tantalum nitride, and any excess precursor is removed before it can decompose and contaminate the layer. The same chemical reactivity that enables deposition also allows for contamination control through proper pulse sequencing.
4Manufacturing precision
If excess thickness of material is deposited on the main surface to achieve sufficient thickness in high form factor holes, then compliance in the hole is improved, but additional material removal is required increasing cost and contamination risk
Solution Approach 1:
The patent applies local quality by controlling deposition conditions specifically for high aspect ratio holes. The pulsed CVD process allows different regions of the substrate to receive appropriate material deposition. The precursor and reactive gas pulses are timed and distributed to ensure uniform thickness in deep holes while minimizing excess deposition on planar surfaces, reducing or eliminating the need for subsequent CMP processing.
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 faster, more compliant, and higher-quality layer deposition, minimizing copper electromigration and extending the reliability of interconnections by reducing contamination and the need for costly material removal processes.
Implementation Method 1
depositing a layer of titanium nitride or tantalum nitride on a main surface of the substrate and on the inner surface of at least one hole extending into at least part of the thickness of said substrate
Implementation Method 2
Physical vapour deposition (PVD) is faster and therefore less expensive
Implementation Method 3
chemical vapour deposition (CVD) provides better compliance than the PVD method
Data Source
AI summary
The invention relates to a method for producing an interconnection comprising a via (V) extending through a substrate (1), said method successively comprising: (a) the deposition of a layer (11) of titanium nitride or tantalum nitride on a main surface (1A) of the substrate and on the inner surface (10A, 10B) of at least one hole (10) extending into at least part of the thickness of said substrate; (b) the deposition of a layer (12) of copper on said layer (11) of titanium nitride or tantalum nitride; and (c) the filling of the hole (10) with copper, said method being characterized in that, during step (a), the substrate (1) is arranged in a first deposition chamber (100), and in that said step (a) comprises the injection of a titanium or tantalum precursor in a gaseous phase into the deposition chamber via a first injection path according to a first pulse sequence, and the injection of a nitrogen-containing reactive gas into the deposition chamber via a second injection path different from the first injection path according to a second pulse sequence, the first pulse sequence and the second pulse sequence being dephased.