Metal Silicide Etch Stop Layers for 3D Nonvolatile Memory Gate Integrity
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Solution Overview
Problem
The existing 3-D structured nonvolatile memory devices with U-shaped channel layers face issues of increased electric resistance and insufficient process margin due to damage from etch processes affecting the pipe connection gate electrode, primarily made of polysilicon.
Innovation Solution
The formation of etch stop layers made of metal silicide over the pipe connection gate electrode to prevent damage and reduce electric resistance, achieved through the fabrication method involving the deposition and annealing of metal layers to create silicide layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pipe connection gate electrode made of polysilicon is used in a 3-D structured nonvolatile memory device with U-shaped channel layers, then the device structure can be formed, but electric resistance increases and the gate electrode may be damaged in subsequent etch processes
Solution Approach 1:
The patent applies composite materials by forming a metal silicide layer over the polysilicon pipe connection gate electrode. This composite structure combines the advantages of polysilicon (compatibility with existing processes) and metal silicide (low resistance and etch resistance), resolving the contradiction between electrode integrity and resistance/etch damage issues
Solution Approach 2:
The metal silicide layer acts as an intermediary protective layer between the polysilicon gate electrode and the subsequent etch processes. This intermediary layer prevents direct exposure of the polysilicon to etchants, thereby preventing damage while also providing the low-resistance pathway needed for reliable operation
2Ease of manufacture
If polysilicon is used for the pipe connection gate electrode, then the fabrication process can proceed, but electric resistance is high
Solution Approach 1:
The composite structure of polysilicon + metal silicide maintains ease of manufacture by keeping polysilicon as the base material (compatible with existing processes) while adding a thin metal silicide layer to reduce resistance, thus achieving both manufacturing ease and low resistance
Solution Approach 2:
The patent changes the electrical parameters of the gate electrode system by adding the metal silicide layer, which has superior electrical conductivity. This parameter change (adding a conductive layer) reduces the overall resistance without fundamentally changing the fabrication process flow
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 use of metal silicide etch stop layers effectively reduces electric resistance and prevents damage to the pipe connection gate electrode during the etching process, ensuring a more reliable and efficient fabrication of nonvolatile memory devices.
Implementation Method 1
forming etch stop layers including metal silicide over the pipe connection gate electrode
Implementation Method 2
forming etch stop layers including metal silicide over the pipe connection gate electrode
Data Source
AI summary
This technology relates to a nonvolatile memory device and a method of fabricating the same. The nonvolatile memory device may include a pipe connection gate electrode over a substrate, one or more pipe channel layers formed within the pipe connection gate electrode, pairs of main channel layers each coupled with the pipe channel layer and extended in a direction substantially perpendicular to the substrate, a plurality of interlayer insulating layers and a plurality of cell gate electrodes alternately stacked along the main channel layers, and etch stop layers including metal silicide and formed over the pipe connection gate electrode.