MRAM MTJ Dielectric Stack Layout for Crosstalk Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As the density of magnetic random access memory (MRAM) cells increases, electrical problems such as RC delay effect and crosstalk become more significant due to their proximity, necessitating improvements in the structure and manufacturing process to mitigate these issues.
Innovation Solution
A semiconductor device and manufacturing method involving a cap layer on a first inter-metal dielectric (IMD) layer, which is removed during patterning to form a magnetic tunnel junction (MTJ) structure, with a second IMD layer surrounding the MTJ structure to improve electrical interference, using materials with varying dielectric constants to enhance isolation and manufacturing yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the density of MRAM cells is increased to improve storage capacity, then the memory cell density is improved, but electrical interference and RC delay effect become more significant
Solution Approach 1:
A cap layer is introduced as an intermediary element between the first IMD layer and the MTJ structure. This cap layer serves as a mediator that enables selective removal during patterning to form isolation structures, thereby reducing electrical interference between adjacent MRAM cells while maintaining high cell density
Solution Approach 2:
The dielectric structure is segmented into multiple layers with different dielectric constants: a first IMD layer with lower dielectric constant surrounding the connection structure, and a second IMD layer with higher dielectric constant surrounding the MTJ structure. This segmentation allows optimized electrical isolation for different functional regions, reducing RC delay and crosstalk effects
2Quantity of substance
If the distance between adjacent MRAM cells is reduced to increase density, then the memory cell density is improved, but crosstalk between cells increases
Solution Approach 1:
Different regions of the device are assigned different dielectric materials with optimized local properties. The first IMD layer with lower dielectric constant is placed in regions requiring signal transmission (connection structures), while the second IMD layer with higher dielectric constant is placed in regions requiring isolation (surrounding MTJ structures), thereby reducing crosstalk between adjacent cells
Solution Approach 2:
The cap layer acts as a temporary intermediary structure that facilitates the formation of precise isolation regions. By removing the cap layer in specific areas during patterning, isolation structures are created that prevent electromagnetic coupling between adjacent MRAM cells, thus reducing crosstalk
Data Source
AI summary
A manufacturing method of a semiconductor device includes the following steps. A first inter-metal dielectric (IMD) layer is formed on a substrate. A cap layer is formed on the first IMD layer. A connection structure is formed on the substrate and penetrates the cap layer and the first IMD layer. A magnetic tunnel junction (MTJ) stack is formed on the connection structure and the cap layer. A patterning process is performed to the MTJ stack for forming a MTJ structure on the connection structure and removing the cap layer. A spacer is formed on a sidewall of the MTJ structure and a sidewall of the connection structure. A second IMD layer is formed on the first IMD layer and surrounds the MTJ structure. The dielectric constant of the first IMD layer is lower than the dielectric constant of the second IMD layer.