Memory Module Control Signal Connector Alignment for Skew Reduction
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Solution Overview
Problem
Prior art semiconductor memory modules with stacked dies experience timing issues due to signal skew caused by uneven connection points of control signals, leading to operational inefficiencies.
Innovation Solution
The semiconductor memory device and module design incorporates a support substrate with strategically positioned connectors for control signals, ensuring that corresponding connectors on opposite sides are aligned and connected at the same points, reducing skew by using through-hole vias to connect clock and control signal lines, thereby improving synchronization between semiconductor memory dies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If control signals are connected to stacked memory dies through conventional via arrangements, then the memory module can be manufactured with standard PCB techniques, but signal skew occurs due to uneven connection points causing timing issues
Solution Approach 1:
The connector array is segmented into multiple groups, with each group assigned to control signals for specific memory dies. This segmentation allows precise positioning of control signal connectors to achieve equal path lengths to different dies, eliminating signal skew while maintaining manufacturability through standardized PCB techniques
Solution Approach 2:
Different areas of the connector array are assigned different functions: control signal connectors are positioned in specific locations optimized for timing synchronization, while data signal connectors are arranged for maximum bandwidth. This local optimization resolves the contradiction by achieving timing precision without requiring complete redesign of the entire connector arrangement
2Ease of manufacture
If control signal connectors are positioned at different locations on the substrate, then manufacturing is simplified using standard PCB vias, but signal skew causes timing delays and operational inefficiencies
Solution Approach 1:
Control signal connectors are positioned to create equipotential paths to the memory dies, ensuring that signals arrive at all dies simultaneously despite traveling through the PCB substrate. This is achieved by carefully selecting connector locations that equalize the electrical path length, resolving the contradiction between manufacturing simplicity and timing precision
3Productivity
If multiple control signals are routed through the substrate to stacked dies, then the memory module achieves higher capacity and performance, but signal skew and timing issues increase
Solution Approach 1:
The PCB substrate acts as an intermediary with strategically positioned control signal connectors that mediate between the memory controller and stacked dies. The connector positions are optimized to balance signal distribution, ensuring timing accuracy is maintained even as memory capacity and operational efficiency increase through additional dies and control signals
Data Source
AI summary
In one embodiment, the semiconductor memory device includes at least a first semiconductor memory die, and a surface of the semiconductor memory device includes a plurality of connectors. At least one of the plurality of connectors is electrically connected to the first semiconductor memory die. The plurality of connectors include at least first and second control signal connectors. The first control signal connector is for a first control signal of a first type, the second control signal connector is for a second control signal of the first type, and the first and second control signal connectors are disposed in different areas of the surface. For example, the first type may be a chip select signal, a clock enable signal, or an on die termination enable signal.