Vertical Dummy Structure Stabilizes Semiconductor Memory Stacks
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Solution Overview
Problem
Current semiconductor devices face challenges in increasing data storage capacity effectively, particularly in designing structures that enhance vertical memory and dummy structures to improve integration and prevent deformation during manufacturing.
Innovation Solution
The semiconductor device incorporates a stack structure with a vertical memory structure penetrating through the memory cell region and a first vertical dummy structure penetrating through the dummy stack region, utilizing these structures as monitoring patterns and alignment keys to stabilize the formation of vertically stacked gate layers and improve integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If vertical memory structures are increased to enhance data storage capacity, then storage capacity is improved, but structural deformation and manufacturing instability occur
Solution Approach 1:
The device is divided into functional regions (memory cell region, gate connection region, dummy region) with distinct stack structures in each. The dummy stack region acts as a separate monitoring zone that does not participate in data storage but provides structural reference for manufacturing alignment and deformation detection.
Solution Approach 2:
The vertical dummy structure serves as an intermediary reference element between the manufacturing process and the actual memory structures. It provides alignment keys and monitoring patterns that mediate the alignment and deformation detection processes, ensuring manufacturing precision without affecting storage capacity.
2Quantity of substance
If more gate layers are stacked vertically to increase memory density, then data storage capacity is improved, but alignment precision deteriorates
Solution Approach 1:
Alignment keys are formed in advance within the dummy stack region before the main memory fabrication process. These pre-formed reference structures provide predetermined alignment markers that guide subsequent stacking operations, ensuring consistent alignment precision even as the number of gate layers increases.
Solution Approach 2:
The dummy stack region replicates the structural characteristics of the memory stack region (alternating insulating and conductive layers) but without functional memory cells. This copying provides a testbed for verifying alignment and structural integrity before committing to full production, maintaining measurement precision across multiple vertical stacks.
3Reliability
If dummy structures are added to monitor and align vertical memory structures, then manufacturing stability is improved, but device complexity increases
Solution Approach 1:
The dummy stack region is merged with the overall device structure and formed using the same fabrication processes as the memory region. The monitoring and alignment functions are combined into the structural layers themselves rather than requiring separate measurement equipment or post-processing steps, adding reliability without proportionally increasing complexity.
Solution Approach 2:
The dummy stack structure serves multiple functions: it provides alignment keys for positioning, monitoring patterns for detecting deformation, and structural reference for vertical stacking. This multi-functionality achieves manufacturing stability through a single integrated structure rather than multiple separate systems.
Data Source
AI summary
A semiconductor device including a stack structure including gate stack and dummy stack regions; a vertical memory structure penetrating through the gate stack region; and a first vertical dummy structure penetrating through a portion of the dummy stack region, wherein the gate stack region includes interlayer insulating and gate layers alternately and repeatedly stacked on each other, the dummy stack region includes dummy insulating and dummy horizontal layers alternately and repeatedly stacked on each other, at least one of the dummy horizontal layers and the gate layers include materials different from each other, an upper surface of the vertical memory structure is at a higher level than an upper surface of the first vertical dummy structure, and a lowermost dummy upper horizontal layer at a higher level than the first vertical dummy structure overlaps the first vertical dummy structure.