3D Semiconductor Memory with Barrier Rib Self-Aligned Contacts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The integration degree of semiconductor devices is limited by the size reduction of 2-D memory cells, and there is a need to enhance the reliability and manufacturing process of semiconductor devices by transitioning to 3-D arrangements.
Innovation Solution
A 3-D semiconductor device is manufactured with a substrate having a memory cell region and contact regions, featuring a string structure of alternately stacked conductive layers and interlayer insulating layers protruding towards the contact region, along with barrier rib patterns that open the conductive layers, allowing for self-aligned contact plugs to be filled between the rib patterns and coupled to the conductive layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If 2-D memory cells are reduced in size to increase integration degree, then integration degree is improved, but further size reduction is limited and reliability deteriorates
Solution Approach 1:
The patent transitions from 2-D memory cell arrangement to 3-D architecture by stacking multiple conductive layers (first conductive layer, second conductive layer, third conductive layer) vertically over the substrate. This vertical stacking enables increased integration degree without further reducing the lateral footprint of individual memory cells, thereby maintaining manufacturing reliability while achieving higher density.
2Quantity of substance
If 3-D semiconductor device structure is implemented to increase integration degree, then integration degree is improved, but manufacturing precision and alignment reliability worsen
Solution Approach 1:
The barrier rib patterns serve as self-aligned reference structures that automatically define the positions of contact plugs. The contact plugs are formed to fill spaces between adjacent barrier rib patterns, ensuring precise alignment without requiring additional alignment steps. This self-service mechanism maintains manufacturing precision in the 3-D structure.
Solution Approach 2:
The barrier rib patterns act as intermediary structures between the stacked conductive layers and the contact plugs. These rib patterns provide a physical reference framework that mediates the alignment process, enabling precise placement of contact plugs relative to the multi-layer conductive structure without direct measurement or complex positioning.
3Ease of manufacture
If barrier rib patterns are spaced apart to open conductive layers, then contact plug formation is enabled, but device complexity increases
Solution Approach 1:
The barrier rib patterns serve multiple functions simultaneously: they act as etch barriers during fabrication, provide self-aligned references for contact plug placement, and serve as structural elements in the final device. This multi-functionality reduces the need for additional separate structures, thereby limiting the increase in device complexity while enabling contact plug formation.
Data Source
AI summary
A semiconductor device includes a substrate including a memory cell region and a contact region, a string structure including conductive layers and first interlayer insulating layers alternately stacked over the substrate and protruded toward a lower layer from the memory cell region toward the contact region, barrier rib patterns spaced apart from one another over the conductive layers in the contact region and configured to open the layers of the conductive layers in the contact region through the spaced spaces, and first contact plugs filled into the space between barrier rib patterns adjacent to each other and coupled to the conductive layers in the contact region.