Redistribution Paths for Microelectronic Packages
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Solution Overview
Problem
Microelectronic devices face challenges in efficiently connecting semiconductor chips to external circuitry due to the presence of long stubs, which cause signal reflection and radiation issues, especially when contacts are arranged remotely from the chip edges.
Innovation Solution
The implementation of redistribution conductive pads and conductive paths with short stubs or no stubs, forming a conductive path that connects these pads to the chip contacts, allowing for efficient signal propagation without dead-ends and minimizing adverse effects, while using materials and structures that are compatible with existing chip fabrication processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If contacts are arranged remotely from chip edges to maximize chip area utilization, then chip area utilization is improved, but signal reflection and radiation issues worsen due to long stubs
Solution Approach 1:
The patent introduces redistribution conductive paths that extend contacts from the chip surface into the vertical dimension by routing them through the substrate to edge locations. This dimensional transition allows contacts to be positioned at chip edges for external connection while maintaining their functional connection to internal circuitry, thereby eliminating long stubs on the chip surface and reducing signal reflection and radiation issues.
Solution Approach 2:
The substrate acts as an intermediary element between the internally located contacts and the external connection points at the chip edges. The redistribution conductive paths embedded in the substrate serve as mediator structures that transfer signals from the contact locations to the edge terminals, effectively replacing the problematic long stubs with controlled impedance paths that minimize signal integrity issues.
2Adaptability or versatility
If long stubs are used to connect remote contacts to external circuitry, then connection flexibility is improved, but signal integrity worsens due to stub-induced reflection and radiation
Solution Approach 1:
The patent extracts the problematic stub section from the connection path by separating the contact location from the external connection point. The stub is eliminated by routing signals through the substrate via redistribution paths, leaving only the necessary short connections at the chip edges. This extraction removes the source of signal reflection and radiation while preserving the ability to connect to external circuitry.
Solution Approach 2:
By transitioning the connection path from a lateral stub on the chip surface to a vertical path through the substrate, the invention eliminates the stub-induced signal integrity problems while maintaining connection flexibility. The substrate provides multiple routing layers and edge locations that offer versatile connection options without requiring long stubs.
3Reliability
If contacts are positioned at chip edges for direct external connection, then signal integrity is improved by eliminating stubs, but chip area utilization worsens due to reduced contact placement flexibility
Solution Approach 1:
The substrate provides a vertical dimension for contact redistribution, allowing contacts to be positioned optimally on the chip surface for area utilization while their signals are routed through the substrate to edge locations for external connection. This dimensional separation decouples the contact placement constraints from the external connection requirements, maintaining both signal integrity and area utilization.
Solution Approach 2:
The substrate serves multiple functions: it provides mechanical support, electrical interconnection, and signal routing capabilities. The redistribution conductive paths in the substrate can route signals from any contact location to any edge terminal, providing universal connectivity that maintains signal integrity while accommodating flexible contact placement for optimal chip area utilization.
Data Source
AI summary
A microelectronic unit has a structure including a microelectronic element such as a semiconductor chip with a first contact disposed remote from the periphery of the structure. The unit further includes first and second redistribution conductive pads disposed near a periphery of the structure and a conductive path incorporating first and second conductors extending toward the first contact, these conductors being connected to one another adjacent the first contact. The conductive path is connected to the first contact, and can provide signal routing from the periphery of the unit to the contact without the need for long stubs. A package may include a plurality of such units, which may be stacked on one another with the redistribution conductive pads of the various units connected to one another.