3D Memory Common Source Line Layout for Thermal Stress Relief
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor devices face challenges in achieving high storage capacity and small size due to stress accumulation during thermal processes, which can cause bending of common source lines, limiting the manufacturing of three-dimensional memory devices with increased element density.
Innovation Solution
The semiconductor device incorporates shifted common source line cuts with varying isolation structure widths to release stress from oxide expansion, preventing bending during thermal manufacturing by alternating insulating and conductive layers, and using sacrificial layers replaced by conductive materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If common source lines are made continuous in stacked planes, then electrical connectivity is improved, but stress accumulation from oxide expansion causes line bending and manufacturing defects
Solution Approach 1:
The common source lines are divided into multiple segments by introducing common source line cuts that extend through the stack. These cuts separate continuous lines into discrete segments, allowing stress from oxide expansion to be released at the cut boundaries while maintaining electrical connectivity through alternative paths in the stacked architecture
Solution Approach 2:
The common source line cuts in adjacent common source lines are positioned asymmetrically (shifted relative to each other in the first direction). This asymmetric arrangement prevents stress accumulation that would occur with aligned cuts, as the stress fields from adjacent cuts do not overlap constructively, thereby preventing line bending while maintaining connectivity
2Productivity
If three-dimensional stacked memory structure is implemented, then storage capacity and element density are increased, but stress from oxide expansion during thermal processes causes manufacturing defects
Solution Approach 1:
The stacked memory structure is segmented by introducing common source line cuts that divide the continuous conductive paths into manageable sections. This segmentation allows the three-dimensional architecture to maintain its high density while accommodating thermal expansion stresses through the discontinuous design
Solution Approach 2:
The isolation structures are designed with varying widths (first width at top, second width at bottom) to provide localized stress management. The different widths create gradient stress distribution that prevents uniform stress accumulation, maintaining line straightness in the critical regions while preserving the overall three-dimensional structure
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
The solution effectively prevents common source lines from bending, ensuring the integrity of the device structure and enabling higher storage capacity in a compact form factor.
Implementation Method 1
The positions of the common source line cuts in the neighboring common source lines are shifted. The stress caused by oxide expansion can be released through the shifted common source line cuts
Data Source
AI summary
The semiconductor device includes a substrate, a stack disposed on the substrate, a first common source line and a second common source line disposed in the stack and connected to the substrate. The stack includes insulating layers and conductive layers alternately arranged. The first common source line and the second common source line are extended along a first direction and are arranged in a second direction that is perpendicular to the first direction. The first common source line includes a first segment and a second segment spaced apart by a first common source line cut. The second common source line includes a third segment and a fourth segment spaced apart by a second common source line cut. The first common source line cut is shifted relative to the second common source line cut in the first direction. A method of forming the semiconductor device is also disclosed.