MCM Redundant Chip-to-Chip Connections for Yield Improvement
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Solution Overview
Problem
The increasing size of multi-chip modules (MCMs) for high-speed communication applications leads to higher costs due to exponential cost increases with substrate size, exacerbated by yield loss from defects in large substrates, making large MCMs cost-prohibitive.
Innovation Solution
Incorporating redundant chip-to-chip communication connections and on-chip multiplexors that can bypass defective signal traces, allowing for the use of substrates with defects and improving yield by selectively routing around faulty connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the substrate size is increased to accommodate more components for high-speed communication, then the bandwidth capability is improved, but the cost increases exponentially and yield loss increases
Solution Approach 1:
The patent divides the MCM into multiple chips (first chip, second chip, third chip) mounted on the substrate, where each chip contains specific functional blocks (ser/des blocks). This segmentation allows the system to achieve high bandwidth through multiple parallel chip-to-chip connections rather than requiring a single large chip, thereby reducing the exponential cost increase associated with large substrate sizes while maintaining the required bandwidth capability.
2Speed
If the substrate size is increased to accommodate more components for high-speed communication, then the bandwidth capability is improved, but the yield loss due to defects increases
Solution Approach 1:
The patent changes the connectivity parameter by implementing multiple redundant chip-to-chip communication connections in addition to the primary connections. When defects are detected in signal traces during testing, the system can reconfigure to use alternative connections, thereby maintaining functionality and improving yield despite the presence of defects in large substrates.
3Reliability
If redundant chip-to-chip communication connections are added, then the yield is improved by bypassing defective traces, but the device complexity increases
Solution Approach 1:
The patent implements multiplexors on each chip that can dynamically select between multiple communication connections (primary and redundant). This multi-functionality allows the same physical infrastructure to serve both normal operation and defect bypass functions, improving yield without requiring completely separate redundant systems, thereby managing complexity through intelligent control rather than physical duplication.
Data Source
AI summary
Disclosed is a multi-chip module (MCM) with redundant chip-to-chip communication connection(s) to minimize the need to discard a chip-mounting layer due to defective signal traces. The MCM includes at least first and second chips mounted on the chip-mounting layer. The chip-mounting layer includes signal traces that are electrically connected between first and second links on the first and second chips, respectively, to form communication connections including at least one redundant communication connection. Instead of being directly connected to the chip-to-chip communication connections, first and second interfaces on the first and second chips are connected via first and second multiplexors, respectively, to selected ones of multiple chip-to-chip communication connections. By employing the multiplexors and the redundant chip-to-chip communication connection(s), chip-to-chip communication connection(s) with defective signal trace(s) can be bypassed. Specifically, during MCM assembly, the multiplexors are programmed to avoid using chip-to-chip communication connections with defective signal traces.