Self-Alignment Method for Recess Channel DRAM
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current semiconductor fabrication methods face challenges in achieving precise overlay control during exposure alignment, leading to mis-alignment issues and cell-to-cell field leakage in dynamic random access memory fabrication, particularly due to limitations in optical lithography and other lithographic technologies.
Innovation Solution
A self-alignment method for recess channel dynamic random access memory that involves forming shallow trench isolation structures, patternizing layers, filling recess trench channels with dielectric and filler materials, and using a passivation layer to self-align structural monomers, eliminating the need for optical lithography and improving integration density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If optical lithography and exposure alignment method are used to patternize the dielectric layer, then the structural monomers can be formed, but mis-alignment occurs leading to cell-to-cell field leakage
Solution Approach 1:
The recess trench channel structure serves as a self-aligning template that automatically positions the structural monomers during the filling process, eliminating the need for external alignment systems. The structural monomers are formed by filling the recess trench channels with conductive material, and the trench channels themselves provide the alignment reference, making the system self-aligning and immune to overlay precision issues.
Solution Approach 2:
The recess trench channel acts as an intermediary structure between the substrate and the structural monomers. It provides a pre-defined geometric template that mediates the positioning relationship, ensuring precise alignment without requiring optical lithography alignment processes.
2Length of moving object
If optical lithography is used for pattern transfer, then the dielectric layer can be patternized, but the wire width cannot be reduced further due to physical limitations
Solution Approach 1:
The invention transitions from two-dimensional planar patterning limitations to three-dimensional vertical structure utilization. By forming recess trench channels that extend vertically into the substrate and filling them to create structural monomers, the design achieves higher integration density without being constrained by lateral lithographic resolution limits.
Solution Approach 2:
The memory structure is segmented into multiple vertical layers including the substrate, recess trench channels, dielectric layer, and structural monomers. This vertical segmentation allows continued scaling by adding more layers rather than reducing lateral dimensions, overcoming the lithography resolution barrier.
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 enhances the yield rate and integration density of integrated circuit products by avoiding mis-alignment issues and cell-to-cell field leakage, while being compatible with existing semiconductor processes without requiring new materials or processes.
Implementation Method 1
selectively performing an ion-implant process to a portion of the target layer 2a according to an electronic circuit design to form an ion-implant region 13a
Data Source
AI summary
A self-alignment method for a recess channel dynamic random access memory includes providing a substrate with a target layer, a barrier layer and a lining layer, wherein the target layer has shallow trench isolation structures; patternizing the lining layer, barrier layer and target layer to form recess trench channels; depositing a dielectric layer onto the recess trench channel; forming an ion doped region in the target layer; removing a portion of the dielectric layer to expose a portion of the recess trench channel; forming a filler layer covered onto the recess trench channel; removing a portion of the filler layer to expose a portion of the recess trench channel; forming a passivation layer onto the recess trench channel; removing the passivation layer on the lining layer; and removing the lining layer to form a plurality of structural monomers disposed at the recess trench channel and protruded from the target layer.