3D Variable-Resistance Memory Bit-Line Structure for Higher Integration
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Solution Overview
Problem
The integration limit of semiconductor devices with memory cells on a single layer has been reached, and there is a need for improved operation reliability and stability in three-dimensional semiconductor structures.
Innovation Solution
A semiconductor device design featuring a bit line with protruding parts and connection parts that intersect word lines, including a variable resistance layer, and a manufacturing method that forms these structures through multiple deposition and patterning steps to minimize damage to the variable resistance layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If memory cells are stacked in a three-dimensional structure to improve integration degree, then the degree of integration is improved, but the structure becomes more complex and manufacturing difficulty increases
Solution Approach 1:
The bit line is divided into multiple protruding parts (first protruding part, second protruding part) and connection parts that extend in different directions. This segmentation allows the bit line to intersect with multiple word lines in a three-dimensional stacked structure, improving integration degree while maintaining manufacturability through modular construction
Solution Approach 2:
The bit line transitions from a planar structure to a three-dimensional structure with protruding parts extending vertically and connection parts extending horizontally. This dimensional change enables the bit line to intersect with word lines in multiple layers, achieving higher integration without excessive complexity
2Ease of manufacture
If conventional manufacturing methods are used for three-dimensional structures, then manufacturing process is simpler, but damage to the variable resistance layer occurs
Solution Approach 1:
The separation insulating layer is formed on the second contact plug before forming the bit line. This preliminary action protects the variable resistance layer from damage during subsequent manufacturing steps, particularly when forming openings and depositing materials, while maintaining ease of manufacture through a straightforward process sequence
Solution Approach 2:
The separation insulating layer acts as an intermediary protective barrier between the bit line formation process and the variable resistance layer. This intermediary layer prevents direct contact and damage during manufacturing while allowing the bit line to be formed with proper structure and alignment
3Ease of manufacture
If bit line structure is simplified, then manufacturing is easier, but intersection with word lines and electrical connection reliability is compromised
Solution Approach 1:
The bit line is segmented into multiple functional parts: protruding parts for intersecting with word lines and connection parts for maintaining electrical continuity. This segmentation enables reliable electrical connections in a three-dimensional structure while keeping each segment simple to manufacture using standard deposition and patterning processes
Solution Approach 2:
Different parts of the bit line have different structures optimized for their specific functions: protruding parts are designed for intersecting with word lines to ensure electrical connection, while connection parts are designed for maintaining continuity and ease of manufacture. This local differentiation achieves both reliability and manufacturability
Data Source
AI summary
A semiconductor device may include a first contact plug, a word line electrically connected to the first contact plug and extending in a first direction, a second contact plug, a bit line extending in a second direction that intersects the first direction, and a memory cell disposed between the word line and the bit line and including a variable resistance layer. The bit line may include a first protruding part that protrudes into the memory cell, a second protruding part that is connected to the second contact plug, and a connection part that connects the first protruding part and the second protruding part and that extends in the second direction.