TiN Bottom Electrode Crystal Orientation for DRAM Yield
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Solution Overview
Problem
The film thickness of Titanium Nitride (TiN) films used in DRAM bottom electrodes is constrained, as thicknesses that are too thick cause internal diameter closure, while thicknesses that are too thin lead to electrode collapse or penetration by hydrogen fluoride during etching, limiting the manufacturing process margin.
Innovation Solution
Forming TiN films with a higher ratio of (111) crystal orientations using Atomic Layer Deposition at specific temperature ranges (380° C to 610° C), which enhances mechanical strength and prevents collapse or penetration, allowing for a thinner film thickness of 45 Å to 140 Å without compromising structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the film thickness of the TiN film is increased, then the mechanical strength and penetration resistance are improved, but the internal diameter part of the cylinder becomes closed
Solution Approach 1:
The patent changes the crystal orientation parameter of the TiN film from conventional orientations to predominantly (111) orientation, which fundamentally alters the material's mechanical properties and enables thinner film thickness while maintaining strength
Solution Approach 2:
The patent applies different crystal orientations to different regions of the TiN film, with (111) orientation concentrated in the radial direction for strength, while other orientations are present in the vertical direction for etching resistance, creating locally optimized properties
2Volume of moving object
If the film thickness of the TiN film is decreased, then the internal diameter space is maintained, but the bottom electrode collapses or HF liquid penetrates through
Solution Approach 1:
The patent changes the crystal orientation parameter of the TiN film to predominantly (111) orientation, which fundamentally alters the material's mechanical properties and enables thinner film thickness while maintaining strength
Solution Approach 2:
The patent creates a composite structure within the TiN film by controlling the distribution of different crystal orientations, where (111) orientation provides mechanical strength and other orientations provide etching resistance, achieving multiple functions in a single material layer
3Volume of moving object
If the film thickness of the TiN film is decreased, then the internal diameter space is maintained, but HF liquid penetrates through to etch silicon dioxide
Solution Approach 1:
The patent changes the crystal orientation parameter of the TiN film to predominantly (111) orientation, which fundamentally alters the material's etching resistance properties, making it impervious to HF liquid penetration even at reduced thickness
Solution Approach 2:
The patent applies different crystal orientations to different regions of the TiN film, with (111) orientation concentrated in the radial direction for strength, while other orientations are present in the vertical direction for etching resistance, creating locally optimized properties
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
Ensures sufficient mechanical strength and prevents hydrogen fluoride penetration, allowing for reduced film thickness without electrode collapse or penetration issues, thereby increasing the manufacturing margin and improving yield ratios.
Implementation Method 1
TiN films with a higher ratio of (111) crystal orientations
Implementation Method 2
prevents hydrogen fluoride penetration
Data Source
AI summary
Disclosed herein is an apparatus that includes a bottom electrode, a top electrode, and a dielectric film disposed between the bottom electrode and the top electrode. The bottom electrode includes TiN having more (111) crystal orientation than (200) crystal orientation.