Non-volatile Resistive Oxide Memory Cell Plasma Etching
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Solution Overview
Problem
The exposure of metal oxide materials to plasma etching during the fabrication of non-volatile resistive oxide memory cells can unpredictably modify their composition and structure, affecting the operation of the memory cells.
Innovation Solution
A method of forming non-volatile resistive oxide memory cells involves depositing a multi-resistive state metal oxide layer between conductive electrodes, with precise etching techniques to pattern the electrodes without using patterned photoresist-comprising etch masks, thereby minimizing the adverse effects of plasma etching on the metal oxide material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plasma etching is used to pattern the electrodes, then the fabrication process is efficient and scalable, but the metal oxide material composition and structure are unpredictably modified
Solution Approach 1:
The patent removes the metal oxide layer from the plasma etching process by using a different material (such as silicon dioxide or silicon nitride) as the etch mask layer. This extraction of the problematic metal oxide from direct plasma exposure eliminates the unpredictable composition and structure modifications while maintaining the efficiency of plasma etching for patterning the electrodes.
Solution Approach 2:
The patent introduces an intermediary layer (etch mask layer made of materials like silicon dioxide, silicon nitride, or carbon) between the plasma etching process and the metal oxide material. This intermediary layer acts as a protective barrier that allows plasma etching to proceed efficiently for electrode patterning while preventing direct plasma exposure to the metal oxide, thus avoiding compositional changes.
2Ease of manufacture
If conventional fabrication processes with patterned photoresist masks are used, then the patterning process is well-established, but the metal oxide material is exposed to plasma etching causing unpredictable modifications
Solution Approach 1:
The patent replaces the conventional photoresist mask with an intermediary etch mask layer made of materials such as silicon dioxide, silicon nitride, or carbon. This intermediary layer serves the same patterning function as photoresist but is plasma-resistant, preventing direct plasma exposure to the metal oxide material while maintaining the well-established plasma etching process for reliable electrode patterning.
Solution Approach 2:
The patent changes the material parameter of the etch mask from organic photoresist to inorganic or plasma-resistant materials (silicon dioxide, silicon nitride, carbon). This parameter change makes the mask layer resistant to plasma etching, allowing the use of conventional plasma-based patterning processes without exposing the metal oxide material to harmful plasma that would cause unpredictable compositional modifications and reduce reliability.
3Manufacturing precision
If the metal oxide material is exposed to plasma, then the etching process can proceed, but the composition and structure of the metal oxide are modified in an unpredictable manner
Solution Approach 1:
The patent introduces a plasma-resistant intermediary layer (etch mask made of silicon dioxide, silicon nitride, or carbon) that allows plasma etching to proceed with high precision for electrode patterning while preventing direct plasma contact with the metal oxide material. This intermediary barrier maintains manufacturing precision without compromising the compositional stability of the metal oxide.
Solution Approach 2:
The patent extracts the metal oxide material from the plasma etching zone by using a separate etch mask layer for patterning. This separation allows the plasma etching process to achieve precise electrode patterning while the metal oxide remains protected from plasma exposure, preventing unpredictable compositional and structural modifications.
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 approach allows for the reliable formation of non-volatile resistive oxide memory cells with stable resistive states, ensuring persistent data storage and reducing the risk of unpredictable changes in the metal oxide material's composition and structure.
Implementation Method 1
the collective material received between the two electrodes is selected or designed to be configured in a selected one of at least two different resistive states to enable storing of information by an individual memory cell. When configured in one extreme of the resistive states, the material may have a high resistance to electrical current. In contrast in the other extreme, when configured in another resistive state, the material may have a low resistance to electrical current.
Implementation Method 2
the three different regions of the memory cell are often patterned by etching using multiple masking and etching steps. Such typically include anisotropic plasma etching through the conductive outer electrode material inwardly at least to the metal oxide which will be the programmable region of the memory cell.
Data Source
AI summary
A method of forming a non-volatile resistive oxide memory cell includes forming a first conductive electrode of the memory cell as part of a substrate. The first conductive electrode has an elevationally outermost surface and opposing laterally outermost edges at the elevationally outermost surface in one planar cross section. Multi-resistive state metal oxide-comprising material is formed over the first conductive electrode. Conductive material is deposited over the multi-resistive state metal oxide-comprising material. A second conductive electrode of the memory cell which comprises the conductive material is received over the multi-resistive state metal oxide-comprising material. The forming thereof includes etching through the conductive material to form opposing laterally outermost conductive edges of said conductive material in the one planar cross section at the conclusion of said etching which are received laterally outward of the opposing laterally outermost edges of the first conductive electrode in the one planar cross section.