Semiconductor Memory Device Third Stack Word Line Segmentation
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Solution Overview
Problem
Conventional semiconductor memory devices lack an efficient configuration for reducing word line length and resistance, leading to suboptimal electrical characteristics.
Innovation Solution
The semiconductor memory device incorporates a third stack between the first and second stacks, with alternately stacked insulating layers of different materials, and strategically positioned pillars and slits to electrically divide word lines, reducing their length and resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional semiconductor memory device configuration is used, then device structure is simple, but word line length and resistance are excessive leading to suboptimal electrical characteristics
Solution Approach 1:
The patent divides the memory device into multiple stacks (first stack, second stack, and third stack) positioned at different locations. The third stack is strategically placed between the first and second stacks to electrically divide word lines, segmenting them into shorter sections. This segmentation reduces word line length and resistance, improving electrical characteristics while maintaining a manageable device structure through systematic arrangement.
Solution Approach 2:
The third stack acts as an intermediary structure between the first and second stacks. It provides intermediate word line division points that electrically segment the word lines without requiring complete restructuring of the entire memory device. This intermediary approach reduces word line length and resistance while avoiding the need for complex special processing, as the third stack uses the same configuration as the other stacks.
2Reliability
If word line length is reduced through special processing, then resistance decreases, but manufacturing complexity increases
Solution Approach 1:
The third stack positioned between the first and second stacks serves multiple functions: it acts as a physical separator between stack groups, provides intermediate word line division points to reduce word line length, and maintains the same internal structure as the other stacks. This universal configuration achieves word line segmentation without requiring special processing, as the third stack is manufactured using the same processes as the first and second stacks.
Data Source
AI summary
A semiconductor memory device includes a substrate, a first stack, a plurality of first columnar portions, a second stack, a plurality of second columnar portions, and a third stack. In the first stack, first conductive layers and first insulating layers are alternately stacked in a thickness direction of the substrate. Each of the plurality of first pillars extends inside the first stack in the thickness direction. In the second stack, second conductive layers and second insulating layers are alternately stacked in the thickness direction. Each of the plurality of second pillars extends inside the second stack in the thickness direction. The third stack is positioned between the first stack and the second stack in the first direction. In the third stack, third insulating layers and fourth insulating layers including a material different from a material of the third insulating layer are alternately stacked in the thickness direction of the substrate.