Deep Trench Capacitor Void Structure for Handling Stress Relief
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Solution Overview
Problem
Deep trench capacitors in semiconductor devices are prone to mechanical stress during handling, which can damage the capacitors and reduce their reliability.
Innovation Solution
Incorporating stress-relief voids within a dielectric fill material layer in deep trench capacitors, where the dielectric fill material has a lower Young's modulus than the electrode and dielectric materials, allowing the voids to absorb mechanical stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If deep trench capacitors are formed with rigid dielectric materials, then high capacitance is achieved, but mechanical stress during handling damages the capacitors
Solution Approach 1:
The patent introduces voids (porous structures) within the dielectric fill material layer to create a stress-relief mechanism. These voids allow the dielectric material to deform elastically under mechanical stress, preventing catastrophic failure of the capacitor structure during handling while maintaining the necessary capacitance through the remaining dielectric material
Solution Approach 2:
The patent changes the physical parameters of the dielectric fill material by incorporating voids, which modifies the effective Young's modulus and Poisson's ratio of the material. This parameter change enables the dielectric to better accommodate mechanical stress without compromising its electrical properties or the capacitor's overall reliability
2Reliability
If voids are incorporated in the dielectric fill material layer, then mechanical stress is absorbed, but device area increases
Solution Approach 1:
The voids are not distributed uniformly throughout the entire device area but are localized within specific regions of the dielectric fill material layer. This local quality approach allows stress relief to be provided only where needed (within the deep trench capacitor structure) without unnecessarily increasing the overall device footprint
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 stress-relief voids effectively absorb mechanical stress applied to the deep trench capacitors during handling, thereby protecting the capacitors from damage and improving their yield and reliability.
Implementation Method 1
the dielectric fill material has a lower Young's modulus than the electrode and dielectric materials, allowing the voids to absorb mechanical stress
Data Source
AI summary
A deep trench is formed in a substrate. A layer stack including at least three metallic electrode layers interlaced with at least two node dielectric layers is formed over the substrate. The layer stack continuously extends into the deep trench, and a cavity is present in an unfilled volume of the deep trench. A dielectric fill material layer including a dielectric fill material is formed in the cavity and over the substrate. The dielectric fill material layer encapsulates a void that is free of any solid phase and is formed within a volume of the cavity. The void may expand or shrink under stress during subsequently handling of a deep trench capacitor including the layer stack to absorb mechanical stress and to increase mechanical stability of the deep trench capacitor.