Hydrogen Passivation of Integrated Circuits via Segmented Film Layers
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Solution Overview
Problem
Hydrogen passivation in integrated circuits becomes increasingly difficult due to materials like TaN blocking hydrogen diffusion and the formation of hydrogen barrier films that prevent hydrogen from reaching the interface, while advanced process flows may degrade materials with high-temperature hydrogen anneals, leading to transistor instability and increased diode leakage.
Innovation Solution
The use of a hydrogen releasing film and a passivation trapping layer, such as silicon nitride, to retain hydrogen near the transistor interface and prevent its diffusion away during thermal processing, combined with a deuterium anneal or hydrogen releasing film to form stable Si—H or Si—D bonds, reducing interface charge and crystal defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrogen annealing is performed to passivate the interface, then interface charge is reduced and transistor stability is improved, but TaN and hydrogen barrier films block hydrogen diffusion and prevent hydrogen from reaching the interface
Solution Approach 1:
The patent segments the passivation function into two distinct layers: a hydrogen releasing film that generates hydrogen and a hydrogen barrier film that traps and directs it. This segmentation allows the system to overcome the blocking effect of TaN by providing a dedicated hydrogen release pathway through the hydrogen releasing film, ensuring hydrogen reaches the interface for passivation while maintaining the beneficial barrier properties of the hydrogen barrier film.
Solution Approach 2:
The hydrogen releasing film acts as an intermediary layer between the hydrogen barrier film and the silicon interface. It mediates the hydrogen delivery process by releasing hydrogen atoms that can diffuse through the hydrogen barrier film to reach the interface, thus solving the contradiction between needing hydrogen for passivation and having hydrogen blocked by barrier films.
2Reliability
If high-temperature hydrogen annealing is used to passivate interfaces, then interface charge is reduced, but advanced process materials are degraded
Solution Approach 1:
The patent changes the temperature parameter of the annealing process by performing it at low temperature (below 200°C) instead of the conventional high temperature. This parameter change allows interface passivation to occur without degrading temperature-sensitive materials, as the low temperature is sufficient to activate hydrogen release and diffusion while being gentle enough to preserve material integrity.
Solution Approach 2:
The patent substitutes the thermal energy mechanism (high-temperature annealing) with a chemical energy mechanism (photo-induced hydrogen release). The photolithography step generates hydrogen in the hydrogen releasing film through photochemical reactions, replacing the need for high-temperature thermal activation and thereby avoiding material degradation.
3Reliability
If conventional hydrogen annealing is performed, then interface passivation is achieved, but additional backend processing steps are required
Solution Approach 1:
The patent merges the passivation function into the existing hydrogen barrier film deposition step. By incorporating the hydrogen releasing film as part of the hydrogen barrier film structure, the passivation function is combined with the barrier function, eliminating the need for separate backend passivation annealing steps and reducing overall process complexity.
Solution Approach 2:
The patent performs the passivation action preliminarily during the hydrogen barrier film formation process. The hydrogen releasing film is deposited and configured to release hydrogen during subsequent processing, so that passivation occurs before final device completion, eliminating the need for additional backend passivation steps.
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 significantly reduces and stabilizes the interface charge, tightens the transistor threshold voltage distribution, and decreases diode leakage, while allowing for the omission of the backend passivation anneal, thereby improving transistor stability and reducing standby current.
Implementation Method 1
a hydrogen releasing film and a passivation trapping layer, such as silicon nitride, to retain hydrogen near the transistor interface
Implementation Method 2
TaN blocking hydrogen diffusion
Implementation Method 3
form stable Si—H or Si—D bonds, reducing interface charge and crystal defects
Implementation Method 4
combined with a deuterium anneal or hydrogen releasing film to form stable Si—H or Si—D bonds
Data Source
AI summary
An integrated circuit with a passivation trapping layer. An integrated circuit with a hydrogen or deuterium releasing layer underlying a passivation trapping layer. Method for forming an integrated circuit having a hydrogen or deuterium releasing layer. Method for forming an integrated circuit having a passivation trapping layer.