Multilayer Trench Capacitor Structure for Selectable Capacitance
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Solution Overview
Problem
The challenge in semiconductor manufacturing is to achieve precise control in fabricating multilayer trench capacitors with high capacitance density while maintaining small device dimensions, which is crucial for advanced device density and performance in integrated circuits like DRAMs.
Innovation Solution
The method involves forming trench capacitor structures with alternating dielectric and conductive layers in trenches of varying depths and widths, and adjusting the number of layer pairs to achieve selectable capacitance, using precise etching and deposition techniques to maintain planarity and facilitate electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If trench capacitor structures with alternating dielectric and conductive layers are formed in trenches of varying depths and widths, then capacitance density is improved, but device dimensions must be reduced to meet integration requirements
Solution Approach 1:
The patent transitions from planar parallel plate capacitors to three-dimensional trench capacitor structures, utilizing vertical depth and lateral width dimensions to increase capacitance density. Multiple alternating dielectric and conductive layers are stacked vertically within trenches, effectively using the third dimension (depth) to pack more capacitance into a smaller footprint area.
Solution Approach 2:
The patent implements nested alternating layers of dielectric and conductive materials within the trench structure, where each layer pair is contained within the previous larger structure. This nested arrangement of N pairs of layers maximizes the use of available space within the trench volume to achieve high capacitance density.
2Manufacturing precision
If precise etching and deposition techniques are used to maintain planarity, then manufacturing precision is improved, but process complexity increases
Solution Approach 1:
The patent divides the capacitor fabrication into separate etching and deposition stages, with each alternating layer pair formed through distinct process steps. This segmentation allows precise control of each layer's thickness and composition independently, maintaining manufacturing precision while managing overall process complexity through systematic repetition of standardized sub-processes.
Solution Approach 2:
The patent performs preliminary planarization and patterning steps before forming each alternating layer pair, ensuring that the substrate surface is properly prepared and aligned before deposition. This preliminary action prevents defects and maintains precision throughout the multi-step fabrication process.
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 allows for customizable capacitance levels in semiconductor devices, enhancing performance and density by optimizing trench dimensions and layer configurations, thereby meeting design criteria for integrated circuits.
Implementation Method 1
depositing a first dielectric layer over a sidewall and a bottom surface of a first trench opening in a substrate, depositing a first conductive layer over the first dielectric layer
Implementation Method 2
etching and deposition techniques to maintain planarity and facilitate electrical connections
Data Source
AI summary
A semiconductor device includes a substrate, a first multilayer capacitor, and a second multilayer capacitor. The first multilayer capacitor includes a first plurality of conductive layers. The semiconductor device further includes a first set of contacts including a first contact electrically connected to a first conductive layer, and a second contact electrically connected to a second conductive layer, wherein the first contact is spaced from the second contact by a first distance. The second multilayer capacitor includes a second plurality of conductive layers. The semiconductor device further includes a second set of contacts including a third contact electrically connected to a third conductive layer, and a fourth contact electrically connected to a fourth conductive layer, wherein the third contact is spaced from the fourth contact by a second distance, and the second distance is different from the first distance.