Vertical Memory Fin Fabrication Process Simplification
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Solution Overview
Problem
The complexity of fabricating vertical memory devices is increased due to the stacking of elements, leading to complications in the manufacturing process, and there is a need to simplify these processes while maintaining compatibility with existing technologies and operational performance.
Innovation Solution
A method involving the formation of semiconductor fin structures on a substrate with doped regions and a trench, where a second doped region is formed under the body regions and extends into the substrate, facilitating electrical connections between fin structures and contacts, and using a hard mask layer with materials like silicon oxide and nitride to pattern and implant dopants, simplifying the process and maintaining compatibility with existing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If vertical memory device structure is adopted to reduce size and prevent short channel effect, then device size is reduced and short channel effect is prevented, but fabrication process complexity increases
Solution Approach 1:
The patent merges the formation of the second doped region with the existing fin structure fabrication process. By forming the second doped region in the substrate under the body regions during the same process steps used to create the fin structures, the method eliminates separate doping steps and simplifies the overall fabrication process while maintaining the vertical memory device architecture
Solution Approach 2:
The fin structures serve multiple functions: they act as the vertical channel structures for memory operation and simultaneously provide a framework for forming the second doped region that extends into the substrate. This multi-functionality reduces the number of separate components and fabrication steps needed
2Length of moving object
If elements are stacked to form vertical structure, then channel length remains unchanged while size is reduced, but fabrication process becomes more complicated
Solution Approach 1:
The second doped region is formed preliminarily in the substrate before the fin structures are fully constructed. By pre-forming this doped region that extends into the substrate, subsequent fabrication steps can proceed without additional doping operations, simplifying the overall manufacturing process
Solution Approach 2:
The doping process is segmented into two distinct regions: the first doped region within the fin structures and the second doped region in the substrate. This segmentation allows each region to be optimized independently while being formed through integrated process steps
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 method significantly simplifies the fabrication of vertical memory devices by facilitating connections between internal elements and maintaining operational performance and compatibility with existing processes, thereby addressing the complexity of vertical memory device manufacturing.
Implementation Method 1
a method of forming the second doped region includes performing an ion implantation process on the substrate with the patterned hard mask layers as masks to implant a dopant in the substrate and form the second doped region
Implementation Method 2
the fabricating method further includes performing a thermal annealing process to cause the dopant to form the second doped region
Data Source
AI summary
Provided is a method for fabricating a memory device, including the following steps. A plurality of semiconductor fin structures is formed on a substrate. Each semiconductor fin structure includes a first doped region and a body region on which the first doped region is disposed, and a trench is disposed between adjacent two semiconductor fin structures. A second doped region is formed in the substrate under the body regions of the semiconductor fin structures and the trenches. A plurality of first contacts are formed on the substrate. A plurality of second contacts are formed on the substrate. Each second contact is electrically connected with the corresponding first doped region.