Monitor Structure for 3D Memory Cell Manufacturing Yield
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
It is challenging to directly monitor the structure of memory cells in semiconductor memory devices with three-dimensionally disposed memory cells, particularly between the semiconductor layer and the word lines, during the manufacturing process.
Innovation Solution
The semiconductor memory device incorporates a monitor structure comprising stacked monitor layers with the same materials as the cell layers, including a first structural body with electrode and insulating layers, and a second structural body with electrodes and an insulating body, allowing for the monitoring of the memory cell structure through the capacitance measurement of a capacitor element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If three-dimensionally disposed memory cells are implemented to increase storage capacity, then the memory device achieves higher density, but direct monitoring of the memory cell structure during manufacturing becomes difficult
Solution Approach 1:
The patent creates a monitor structure that is a simplified copy of the actual memory cell stack. This monitor structure includes monitor insulating layers and monitor semiconductor layers that replicate the material composition and stacking sequence of the real memory cells, but without the complex three-dimensional interconnections. By measuring this two-dimensional copy structure, the patent enables indirect monitoring of the three-dimensional memory cell formation process, resolving the contradiction between high density implementation and manufacturing monitoring capability
Solution Approach 2:
The monitor structure serves as an intermediary between the manufacturing process and the measurement system. Instead of attempting to directly measure the complex three-dimensional memory cells embedded in the stack, the patent uses this intermediate monitor structure that can be accessed and measured through standard planar measurement techniques, while still reflecting the quality of the three-dimensional cell formation
2Measurement precision
If monitor structures are added to enable manufacturing monitoring, then measurement capability is improved, but device complexity increases
Solution Approach 1:
The patent segments the memory device into functional regions: the active three-dimensional memory cell array and the separate monitor structure region. This segmentation allows the monitor function to be isolated from the main memory functionality, enabling independent optimization of each. The monitor structure uses simplified two-dimensional layers rather than full three-dimensional stacks, reducing local complexity while maintaining measurement capability
Solution Approach 2:
The monitor structure acts as a sacrificial or disposable element that serves its measurement purpose and can be removed or overwritten in subsequent manufacturing steps. It does not need to maintain long-term structural integrity like the main memory cells, allowing for simpler construction using standard layer deposition techniques without requiring complex three-dimensional alignment
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
This solution enables effective monitoring of the memory cell structure, enhancing the manufacturing yield by allowing for real-time feedback on manufacturing conditions and improving the precision of the memory cell array formation.
Implementation Method 1
The insulating body includes same material as a material of the first insulating layer, and has almost same thickness as a thickness of the first insulating layer
Data Source
AI summary
A semiconductor memory device includes a stacked body including a plurality of word lines; a semiconductor layer extending through the word lines; a memory cell provided at a part where the semiconductor layer crosses one of the word lines, the memory cell including a plurality of cell layers, the cell layers including a first insulating layer; and at least one of a first structural body and a second structural body provided around the stacked body. The first structural body includes a plurality of monitor layers including same materials respectively as materials of the cell layers. The second structural body includes a first electrode, a second electrode and an insulating body positioned between the first electrode and the second electrode. The insulating body includes same material as a material of the first insulating layer, and has almost the same thickness as a thickness of the first insulating layer.