Semiconductor Constructions with Silicon Support Layer
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Solution Overview
Problem
The formation of high aspect ratio openings in semiconductor fabrication for capacitors often results in bowing and twisting issues, which complicate the fabrication of tall, thin capacitors and can lead to toppling, making it difficult to maintain the desired orientation and structure.
Innovation Solution
A method involving a stack of materials with a non-oxidized silicon layer between oxide-containing and nitride-containing layers, where the silicon layer is selectively etchable and provides additional support to prevent bowing and twisting, allowing for the formation of stable high aspect ratio openings for capacitor fabrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If tall, thin capacitors are formed in high aspect ratio openings to reduce footprint, then area efficiency is improved, but structural stability deteriorates due to toppling and bowing
Solution Approach 1:
The lattice structure is divided into multiple discrete pillars arranged in a grid pattern, with each pillar providing localized support. The openings between pillars are filled with dielectric material, creating a segmented composite structure that provides both mechanical support and electrical functionality.
Solution Approach 2:
The lattice structure combines multiple materials including silicon nitride pillars, oxide-containing dielectric material, and conductive plugs. This composite approach allows each material to contribute its specific properties: mechanical strength from silicon nitride, electrical insulation from oxide material, and conductivity from metal plugs.
2Stability of the object's composition
If lattice structures are formed to support tall, thin capacitors, then structural stability is improved, but manufacturing complexity increases due to multiple etching steps
Solution Approach 1:
The lattice structure is formed as a preliminary support framework before capacitor fabrication begins. The silicon nitride pillars and oxide layers are deposited and patterned in advance, creating a pre-configured support structure that guides subsequent capacitor formation steps.
Solution Approach 2:
The oxide-containing layer serves as an intermediary sacrificial layer that is selectively removed to create openings. This intermediary layer facilitates the formation of high aspect ratio openings by providing a controlled etching pathway while protecting surrounding structures.
3Area of stationary object
If high aspect ratio openings are formed for capacitor fabrication, then area efficiency is improved, but manufacturing precision deteriorates due to bowing and twisting
Solution Approach 1:
The lattice structure provides localized support at specific positions within the opening, with silicon nitride pillars strategically placed to prevent bowing and twisting. The support is concentrated where most needed rather than uniformly distributed, allowing precise control of opening geometry.
Solution Approach 2:
The problem of maintaining opening geometry is solved by adding vertical support elements (pillars) into the third dimension. Instead of relying solely on planar support, the lattice structure extends vertically with multiple tiers of pillars that provide three-dimensional structural control.
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 effectively alleviates or eliminates bowing and twisting issues, improving the stability and orientation of capacitors within the openings, thereby enhancing the reliability of subsequent capacitor fabrication processes.
Implementation Method 1
the silicon layer is selectively etchable
Implementation Method 2
provides additional support to prevent bowing and twisting
Data Source
AI summary
Some embodiments include methods of forming semiconductor constructions. Oxide is formed over a substrate, and first material is formed over the oxide. Second material is formed over the first material. The second material may be one or both of polycrystalline and amorphous silicon. A third material is formed over the second material. A pattern is transferred through the first material, second material, third material, and oxide to form openings. Capacitors may be formed within the openings. Some embodiments include semiconductor constructions in which an oxide is over a substrate, a first material is over the oxide, and a second material containing one or both of polycrystalline and amorphous silicon is over the first material. Third, fourth and fifth materials are over the second material. An opening may extend through the oxide; and through the first, second, third, fourth and fifth materials.