RRAM Memory Cell Structure Without Conductive Pillar Damage
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Solution Overview
Problem
Conventional methods for forming memory cells, particularly in resistive random-access memory (RRAM) devices, face challenges such as damage to conductive pillars during etching and chemical mechanical polishing, leading to unreliable connections between selectors and memory elements due to oxidation, etch damage, and dishing behavior, which limits device yield and manufacturing precision.
Innovation Solution
The solution involves forming a memory cell without a conductive pillar between the selector and the memory element, allowing direct contact and ensuring a secure electrical connection, using a method that includes forming a dielectric layer, an electrode layer, and a memory material stack, with a connecting structure that allows for patterning and planarization without the need for a conductive pillar, thereby enhancing the connection reliability and manufacturing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductive pillar is used to connect the selector and memory element, then the electrical connection is established, but the conductive pillar suffers damage during etching and chemical mechanical polishing processes
Solution Approach 1:
The patent removes the conductive pillar component entirely from the memory cell structure. The selector is directly connected to the memory element through a trench formation process, eliminating the intermediate conductive pillar that caused manufacturing issues during etching and chemical mechanical polishing processes.
2Ease of manufacture
If conventional etching and chemical mechanical polishing processes are used to form conductive pillars, then the memory cell structure is created, but oxidation and etch damage occur leading to unreliable connections
Solution Approach 1:
Instead of forming conductive pillars through etching and then planarizing them, the patent inverts the approach by directly forming trenches through the dielectric layer and filling them with conductive material in a single integrated process, eliminating the need for separate etching and chemical mechanical polishing steps that caused oxidation and damage.
3Reliability
If a conductive pillar structure is used, then the selector and memory element can be connected, but dishing behavior occurs during chemical mechanical polishing limiting device yield
Solution Approach 1:
The patent extracts and removes the conductive pillar structure that caused dishing behavior during chemical mechanical polishing. By directly forming trenches and filling them with conductive material, the process eliminates the planarization step that caused dishing, thereby improving device yield while maintaining reliable connections.
Data Source
AI summary
A memory cell includes a memory device, a connecting structure, an insulating layer and a selector. The connecting structure is disposed on and electrically connected to the memory device. The insulating layer covers the memory device and the connecting structure. The selector is located on and electrically connected to the memory device, where the selector is disposed on the insulating layer and connected to the connecting structure by penetrating through the insulating layer.