BEOL Dielectric Memory Structure for DRAM Data Retention
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Solution Overview
Problem
Dynamic random access memory (DRAM) cells in semiconductor devices are volatile, losing data when power is removed, and existing solutions for non-volatile memory integration in back-end-of-line (BEOL) regions are complex and costly, requiring additional masking steps and processing time.
Innovation Solution
Incorporating a dielectric-based one-time programmable (OTP) anti-fuse or resistive random access memory (ReRAM) structure in the BEOL region, which uses a programmable resistance-based memory cell to store data, allowing for selective modification of electrical resistance without additional masking steps, enabling both caching and long-term storage alongside DRAM cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If non-volatile memory is integrated in BEOL region using existing solutions, then data retention capability is improved, but device complexity and manufacturing cost increase due to additional masking steps and processing time
Solution Approach 1:
The patent merges non-volatile memory functionality with existing BEOL dielectric layers by forming programmable resistance-based memory cells within the interlayer dielectric structure. This integration approach combines volatile DRAM caching with non-volatile storage in the same BEOL region, eliminating the need for separate memory structures and reducing overall device complexity while maintaining data retention capability.
Solution Approach 2:
The dielectric-based memory structure serves multiple functions: it acts as both the interlayer dielectric for BEOL routing and the storage medium for non-volatile memory. The same dielectric layer provides electrical isolation for conductive interconnects while simultaneously enabling resistance-based data storage, thereby reducing the number of processing steps and masking operations required.
2Duration of action of stationary object
If non-volatile memory is integrated in BEOL region using existing solutions, then data retention capability is improved, but manufacturing time and cost increase due to additional masking steps
Solution Approach 1:
The patent combines non-volatile memory formation with existing BEOL dielectric layer deposition and patterning processes. By forming memory cells within already-present dielectric layers rather than adding separate memory structures, the manufacturing timeline is preserved while achieving data retention functionality.
Solution Approach 2:
The patent utilizes dielectric layers that are already deposited and patterned as part of the standard BEOL process before non-volatile memory functionality is introduced. This preliminary preparation of dielectric structures eliminates the need for additional masking and deposition steps that would extend manufacturing time.
3Ease of manufacture
If dielectric-based OTP anti-fuse or ReRAM structure is used, then manufacturing cost and processing time are minimized, but data retention capability must be maintained
Solution Approach 1:
The patent changes the electrical resistance parameter of the dielectric material through programming operations to store data. By modifying resistance states (high resistance for logic 0, low resistance for logic 1) within the existing dielectric layer, the system achieves non-volatile data storage without requiring additional materials or complex structures, thereby maintaining manufacturing simplicity while ensuring data retention.
Solution Approach 2:
The patent replaces physical or chemical changes (such as phase transitions or material transformations) with electrical resistance modification for data storage. This substitution allows data to be retained non-volatily through electrical state changes in the dielectric material rather than requiring mechanical or chemical structures, simplifying the manufacturing process while maintaining data retention capability.
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 allows for minimal impact on back-end processing costs and time, integrating non-volatile memory with volatile DRAM cells in the BEOL region, ensuring data retention and efficient processing by using similar techniques and operations.
Implementation Method 1
a portion of the dielectric layer between the second source/drain region and the select line conductive structure... functions as a programmable resistance-based memory cell region
Data Source
AI summary
A semiconductor device may include a non-volatile memory structure that may be formed in a back end of line (BEOL) region of a semiconductor device. The non-volatile memory structure may include a dielectric-based one-time programmable (OTP) anti-fuse memory structure or a dielectric-based resistive random access memory (ReRAM), among other examples. The non-volatile memory structure may be selectively programmed based on modifying an electrical resistance of the non-volatile memory structure, and may retain data stored in the non-volatile memory structure even when electrical power is removed from the semiconductor device.