3D Memory Dummy Block Grounding to Prevent Charge Buildup
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Solution Overview
Problem
Existing semiconductor manufacturing processes face challenges in providing effective electrical grounding for metal interconnect structures during processing steps, leading to issues such as charge accumulation and void formation in memory devices.
Innovation Solution
A bonded three-dimensional memory device is developed with temporary electrical grounding paths in a dummy memory block, utilizing conductive via structures that extend between metal interconnect structures and a backside dielectric layer for proper electrical grounding, preventing charge accumulation and void formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal interconnect structures are formed during processing steps, then electrical connectivity is established, but charge accumulation and void formation occur due to lack of electrical grounding
Solution Approach 1:
The patent applies preliminary action by forming temporary electrical grounding paths through conductive via structures in the dummy memory block before the metal interconnect structures are fully formed. These grounding paths are established in advance to prevent charge accumulation and void formation during subsequent processing steps, such as electroplating. The grounding paths are removed after serving their protective function, having prevented the harmful effects during the critical formation period.
Solution Approach 2:
The patent uses an intermediary approach by introducing a dummy memory block with conductive via structures as a temporary mediator. This dummy block serves as an intermediate structure that provides the necessary electrical grounding during processing without being part of the final functional device. The conductive vias in the dummy block act as temporary grounding paths that mediate between the metal interconnect structures and the substrate, preventing charge accumulation during electroplating and other processing steps.
2Reliability
If dummy memory block with conductive via structures is added, then electrical grounding is provided, but device complexity increases
Solution Approach 1:
The patent applies universality by designing the dummy memory block to serve multiple functions simultaneously. The dummy block not only provides temporary electrical grounding during processing but also maintains structural consistency with the functional memory blocks, ensuring uniform electroplating conditions across the entire substrate. This multi-functional approach allows a single structure to address both grounding requirements and process uniformity, reducing the need for additional separate components or steps.
Solution Approach 2:
The patent implements the discarding and recovering principle by forming temporary grounding paths in the dummy memory block that are intentionally removed after serving their protective function. The conductive via structures are created, used to prevent charge accumulation and void formation during critical processing steps, and then discarded in a controlled manner. This temporary structure is recovered (removed) once no longer needed, having fulfilled its purpose without becoming part of the final device.
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 solution ensures reliable electrical grounding of metal interconnect structures, reducing charge accumulation and voids, thereby enhancing the stability and performance of memory devices during processing.
Implementation Method 1
a conductive via structure vertically extending between one of the memory-side metal interconnect structures and the backside dielectric material layer
Data Source
AI summary
Memory stack structures including electrically floating vertical semiconductor channels can vertically extend through an alternating stack of insulating layers and electrically conductive layers. Metal interconnect structures connected to the electrically floating vertical semiconductor channels can be temporarily electrically grounded by a connection via structure that contacts a semiconducting or conductive carrier substrate, which is subsequently removed. The conductive via structure may be formed through the alternating stack, through a vertical stack of dielectric material plates and the insulating layers, or through a dielectric material portion. The conductive via structure may be connected to at least one bit line. In case the conductive via structure is temporarily connected to a plurality bit lines, the conductive via structure can be subsequently isolated from the bit lines.