Laminated TiN Electrode Layers for High-Aspect-Ratio DRAM Capacitors
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Solution Overview
Problem
As DRAM technology advances to smaller nodes, the mechanical strength of Titanium Nitride (TiN) materials used in capacitors is insufficient, leading to structural collapse under stress due to increased depth-to-width ratios in capacitive structures.
Innovation Solution
A method for manufacturing electrode layers involves forming a doped TiN layer as a first electrode layer, followed by a TiN layer or a work function layer as a second electrode layer, enhancing mechanical strength and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If TiN material is used as capacitor electrode material, then heat stability and compatibility with high-K dielectric layer are improved, but mechanical strength is insufficient leading to structural collapse
Solution Approach 1:
The patent applies composite materials by forming a laminated structure comprising a first TiN layer and a second TiN layer with different crystal orientations. The first TiN layer provides heat stability and compatibility, while the second TiN layer with (100) crystal orientation provides enhanced mechanical strength and stress resistance, preventing capacitor collapse.
Solution Approach 2:
The patent applies local quality by controlling different crystal orientations in different layers. The first TiN layer has specific crystal orientation for heat stability, while the second TiN layer is specifically oriented with (100) crystals to provide mechanical strength in critical stress directions, allowing each layer to optimize its properties for its specific function.
2Productivity
If capacitor depth-to-width ratio is increased for miniaturization, then storage capacity is improved, but mechanical strength decreases causing collapse
Solution Approach 1:
The laminated composite structure with differently oriented TiN layers provides enhanced mechanical strength that can support increased depth-to-width ratios. The second TiN layer with (100) orientation specifically reinforces the structure against collapse while maintaining the high storage capacity enabled by the increased depth-to-width ratio.
Solution Approach 2:
The patent changes the crystal orientation parameter of the TiN layers, specifically creating a second layer with (100) orientation that has superior mechanical properties. This parameter change allows the capacitor to achieve higher depth-to-width ratios without structural collapse, thereby increasing storage capacity.
3Stability of the object's composition
If doped TiN layer is formed to improve mechanical strength, then structural stability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent changes the doping parameter of the TiN layer, introducing dopants to modify the crystal structure and enhance mechanical strength. This parameter change improves structural stability while the doping process can be integrated into existing manufacturing workflows, managing complexity.
Solution Approach 2:
The doped TiN layer is combined with an undoped or differently doped TiN layer in a laminated structure. This composite approach allows the doped layer to provide structural stability while the overall manufacturing process remains manageable by dividing the complex doped structure into discrete, sequentially formed layers.
Data Source
AI summary
The application relates to an electrode layer, a capacitor and methods for electrode layer and capacitor manufacture. The method for electrode layer manufacture comprises the following steps: forming a first electrode layer, the first electrode layer comprising a doped Titanium Nitride (TiN) layer; and forming a second electrode layer on the surface of the first electrode layer, the second electrode layer comprising a TiN layer or a work function layer.