TiN-Based Film Segmentation for Barrier and Uniformity
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Solution Overview
Problem
The miniaturization of semiconductor devices leads to thinner TiN films used as barrier films and gate metals, which face challenges in maintaining high barrier properties and uniformity of threshold voltage due to increased penetration of F-based gases and variation in crystal grain size.
Innovation Solution
A TiN-based film is formed by alternately laminating a TiON film with an oxygen content of 50% or above and a TiN film on a substrate, utilizing Atomic Layer Deposition (ALD) to achieve a small crystal size and suppress crystallization, thereby enhancing barrier properties and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the TiN film thickness is reduced to minimize tungsten wiring resistance, then the wiring resistance decreases, but F-based gas penetrates through grain boundaries causing deterioration of barrier property
Solution Approach 1:
The TiN barrier film is segmented into multiple thin layers (first TiN layer, TiON layer, second TiN layer) instead of using a single thick layer. This segmentation creates multiple barrier interfaces that collectively prevent F-based gas penetration while allowing the total tungsten thickness to be minimized for low resistance
Solution Approach 2:
The invention uses a composite structure combining TiN and TiON materials in alternating layers. The TiON layer with high oxygen content (50-80 at%) provides enhanced barrier properties against F-based gas, while the TiN layers maintain good conductivity, creating a composite material system that simultaneously achieves low resistance and high barrier performance
2Speed
If the TiN film thickness is reduced to minimize gate metal capacitance, then the device speed increases, but variation in crystal grain size causes non-uniformity of threshold voltage
Solution Approach 1:
The gate metal TiN film is segmented into multiple thin alternating layers of TiN and TiON. This segmentation ensures that each individual layer has controlled and uniform crystal grain size, and the cumulative effect of multiple layers provides overall uniformity in threshold voltage while keeping the total gate metal thickness small for high device speed
Solution Approach 2:
The invention changes the compositional parameter by introducing TiON layers with high oxygen content (50-80 at%) into the TiN film structure. This parameter change affects the crystal grain formation and distribution, leading to more uniform grain size across the film thickness, which in turn ensures uniform threshold voltage characteristics
3Ease of manufacture
If a single TiN layer is used as barrier film, then the manufacturing process is simple, but the barrier property deteriorates when film thickness is reduced
Solution Approach 1:
The barrier film is segmented into multiple alternating layers of TiN and TiON that can be formed using sequential deposition processes. While more complex than a single layer, the segmented structure can be implemented using standard ALD or sputtering equipment with modified process sequences, achieving a balance between manufacturing complexity and enhanced barrier performance
Solution Approach 2:
The invention employs a composite material system of TiN and TiON layers. The TiON component with high oxygen content provides superior barrier properties against F-based gas penetration, while the TiN components maintain electrical conductivity. This composite approach enhances barrier performance without requiring excessively complex manufacturing processes
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 TiN-based film achieves a high barrier property despite reduced thickness and uniform crystal grain distribution, effectively addressing the issues of F-based gas penetration and threshold voltage non-uniformity.
Implementation Method 1
utilizing Atomic Layer Deposition (ALD) to achieve a small crystal size and suppress crystallization
Data Source
AI summary
A TiN-based film includes TiON films having an oxygen content of 50% or above and TiN films which are laminated alternately on a substrate. In a TiN-based film forming method, a TiON film having an oxygen content of 50 at % or above and a TiN film are alternately formed on a substrate.