Buffer Chip Stacked Memory Package Electrical Loading Reduction
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Solution Overview
Problem
As the demand for increased memory capacity in computer systems, such as data centers and servers, grows due to artificial intelligence and big data requirements, existing methods face challenges in adding memory while maintaining low latency and high bandwidth, leading to increased electrical loading on memory module controllers.
Innovation Solution
A semiconductor package is designed with a buffer chip and multiple memory chips stacked on a package substrate, where the buffer chip communicates with a memory controller through package terminals and wires, reducing loading by buffering control signals and data transmission between the memory controller and memory chips, and allowing for independent latency settings for each memory chip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If memory capacity is increased by adding more memory chips to a computer system, then the amount of memory available for processing increases, but the electrical loading on the memory module controller increases and latency increases
Solution Approach 1:
The patent divides the memory system into multiple independent memory chips (first memory chip, second memory chip, etc.) that can be stacked vertically on the package substrate. Each memory chip operates independently with its own control signals, allowing the memory capacity to be increased by adding more chips without proportionally increasing the controller's electrical loading, as the control signals are distributed and managed separately for each chip.
Solution Approach 2:
The patent transitions from a horizontal expansion approach to a vertical stacking approach. Memory chips are arranged in multiple layers stacked on top of each other on the package substrate, utilizing the vertical dimension (Z-axis) rather than only horizontal expansion. This dimensional change allows increased memory capacity while maintaining compact form factor and reducing the electrical loading distance between controller and memory chips.
2Quantity of substance
If more memory chips are added to increase memory capacity, then the total memory available increases, but the latency increases and bandwidth is compromised
Solution Approach 1:
The patent implements separate control signal paths for each memory chip through dedicated bonding pads and wires on the package substrate. This segmentation allows simultaneous or independent access to multiple memory chips, enabling parallel operations that reduce overall latency. The controller can issue commands to multiple chips concurrently, and the buffer chip can manage data flow between chips independently, preventing the latency that would result from sequential access to a single consolidated memory block.
Solution Approach 2:
The patent introduces a buffer chip as an intermediary component between the memory controller and the multiple memory chips. The buffer chip receives control signals from the controller, buffers them, and then transmits them to the appropriate memory chips. This intermediary layer enables precise timing control and latency management for each chip independently, allowing the system to optimize access patterns and reduce overall latency while maintaining high memory capacity.
3Quantity of substance
If memory capacity is increased by adding more memory chips, then the total memory available increases, but the electrical loading on the memory module controller increases
Solution Approach 1:
The patent segments the control architecture by providing dedicated control signal lines and bonding pads for each memory chip. Instead of using a single shared control bus that would become increasingly complex and heavily loaded as more chips are added, each chip has its own control path. This segmentation distributes the electrical loading across multiple independent channels, preventing the controller from becoming a bottleneck and reducing the overall device complexity despite increased memory capacity.
Solution Approach 2:
The patent moves the memory chips from a planar arrangement to a three-dimensional stacked configuration on the package substrate. This vertical arrangement reduces the trace lengths and wire lengths required for connecting the controller to each memory chip, thereby reducing parasitic capacitance and electrical loading on the controller. The stacked configuration also allows for more efficient use of the package substrate real estate, accommodating more chips without proportionally increasing interconnect complexity.
Data Source
AI summary
A semiconductor package may include: a package substrate including a plurality of terminals for communication with a memory controller and a plurality of bonding pads for communication inside a package; a buffer chip located on the package substrate; a plurality of memory chips stacked on the buffer chip; and a plurality of wires connecting the plurality of bonding pads and the plurality of memory chips. The buffer chip may communicate with the memory controller through the plurality of terminals of the package substrate, and the plurality of memory chips may communicate with the buffer chip through the plurality of wires and the plurality of bonding pads of the package substrate.