In-Situ MIM Stack Encapsulation for RERAM Oxygen Control
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Solution Overview
Problem
Conventional RERAM cell processing methods expose the memory cell dielectric to oxygen during multiple chamber transfers, affecting oxygen content control and reducing throughput.
Innovation Solution
A single chamber process for etching and encapsulating the MIM stack within a plasma etch chamber, where a non-oxygen-containing dielectric encapsulation layer is deposited in-situ to minimize oxygen ingress, using silicon-containing precursors like SiCl4 and SiF4, and an oxygen-free plasma etch chemistry for spacer etch to remove the encapsulation layer from the top surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the MIM stack is etched and then encapsulated in a separate deposition chamber, then the oxygen content control is improved, but the throughput is reduced due to multiple chamber transfers
Solution Approach 1:
The patent combines the etching process and encapsulation process into a single plasma etch chamber. The encapsulation layer is deposited in-situ within the same chamber where etching occurs, eliminating the need for separate chamber transfers. This merging of operations maintains oxygen content control while improving throughput by reducing process time and chamber transitions.
Solution Approach 2:
The patent implements continuous processing by maintaining the substrate within the plasma etch chamber throughout both etching and encapsulation operations. The encapsulation layer is deposited without removing the substrate from the chamber, ensuring continuous useful action and preventing oxygen exposure during chamber transfers, thereby maintaining both precision and productivity.
2Manufacturing precision
If multiple chamber transfers are performed for etching and encapsulation, then the oxygen content control is improved, but the exposure time to oxygen is increased
Solution Approach 1:
The substrate remains continuously within the plasma etch chamber during both etching and encapsulation operations. This continuous processing eliminates interruptions and exposure to oxygen-containing environments during chamber transfers, thereby reducing oxygen exposure time while maintaining precise oxygen content control through in-situ encapsulation.
3Productivity
If the encapsulation layer is deposited in-situ in the plasma etch chamber, then the throughput is maintained, but the oxygen content control may be compromised
Solution Approach 1:
The encapsulation layer is deposited within the plasma etch chamber using an oxygen-free plasma environment. This inert atmosphere prevents oxygen ingress into the memory cell dielectric during the encapsulation process, maintaining oxygen content control while enabling in-situ processing that preserves throughput.
Solution Approach 2:
The plasma environment acts as an intermediary medium that enables both etching and encapsulation operations within the same chamber. By using plasma as the processing medium, the patent achieves in-situ encapsulation without oxygen exposure, maintaining both productivity and manufacturing precision.
4Manufacturing precision
If conventional separate chamber processing is used, then the oxygen content control is improved, but the process complexity is increased
Solution Approach 1:
The patent merges etching and encapsulation operations into a single plasma etch chamber, reducing the number of processing chambers and simplifying the overall process flow. This consolidation maintains oxygen content control through in-situ encapsulation while decreasing process complexity by eliminating multiple chamber transfers and associated process steps.
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 effectively controls oxygen content in the memory cell dielectric while maintaining throughput by encapsulating the MIM stack in-situ, reducing exposure to oxygen and preventing oxygen ingress during subsequent processing steps.
Implementation Method 1
etching the first electrode layer, the memory cell dielectric layer and the second electrode layer to form one or more Metal-Insulator-Metal (MIM) stacks... wherein said etching is performed within at least one plasma etch chamber
Implementation Method 2
depositing an encapsulation layer onto the one or more MIM stacks and surrounding surfaces, wherein said depositing is performed within the at least one plasma etch chamber
Data Source
AI summary
Methods are provided herein for improving oxygen content control in a Metal-Insulator-Metal (MIM) stack of an RERAM cell, while also maintaining throughput. More specifically, a single chamber solution is provided herein for etching and encapsulating the MIM stack of an RERAM cell to control the oxygen content in the memory cell dielectric of the RERAM cell. According to one embodiment, a non-oxygen-containing dielectric encapsulation layer is deposited onto the MIM stack in-situ while the substrate remains within the processing chamber used to etch the MIM stack. By etching the MIM stack and depositing the encapsulation layer within the same processing chamber, the techniques described herein minimize the exposure of the memory cell dielectric to oxygen, while maintaining throughput.