Organic Interposer Crosstalk Suppression via Impedance Control
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Solution Overview
Problem
The use of silicon interposers in semiconductor devices results in high manufacturing costs and limited flexibility in wiring layout due to their high wiring density, which can lead to increased crosstalk between bus signals, while organic interposers offer lower costs but struggle with maintaining high-speed signal transmission due to lower wiring density and increased crosstalk.
Innovation Solution
The semiconductor device employs organic interposers with strategically designed signal wiring configurations, including output and input circuits that manage impedance to generate reflected waves in specific phases, and sets average dynamic signal delay times to suppress crosstalk, allowing for longer wiring lengths without reducing wiring density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If silicon interposers are used to achieve high wiring density and high-speed signal transmission, then signal transmission speed is improved, but manufacturing cost increases
Solution Approach 1:
The patent changes the material parameter of the interposer from silicon to organic material, which fundamentally alters the cost structure while maintaining electrical performance. This substitution allows the use of flexible PCB manufacturing processes instead of expensive silicon wafer fabrication, directly resolving the cost issue while preserving high-speed signal transmission capabilities through proper wiring design
Solution Approach 2:
The patent employs organic interposer materials that are inherently cheaper than silicon, accepting that these materials may have different longevity characteristics. The cost advantage of organic materials is leveraged to reduce overall system cost, particularly for applications where the interposer serves its function effectively within the required operational lifespan
2Quantity of substance
If silicon interposers with high wiring density are used, then wiring density is improved, but crosstalk between bus signals increases
Solution Approach 1:
The patent applies different design qualities to different parts of the wiring system. Ground wires are designed with larger cross-sectional areas and specific routing patterns to provide local shielding and noise absorption. Signal wires maintain narrow widths for high density but are strategically positioned relative to ground wires. This local differentiation of wire properties allows high overall wiring density while minimizing crosstalk through localized electromagnetic field management
Solution Approach 2:
The patent introduces ground wires as intermediary elements between signal wires. These ground wires act as electromagnetic shields and reference planes, mediating the electromagnetic fields between adjacent signal conductors. By positioning ground wires in specific patterns (such as alternating with signal wires or forming protective layers), the patent reduces mutual interference while maintaining the high wiring density required for high-speed data transmission
3Ease of manufacture
If organic interposers are used to reduce manufacturing cost, then cost is reduced, but crosstalk between bus signals increases due to lower wiring density
Solution Approach 1:
The patent transitions from two-dimensional planar wiring arrangements to three-dimensional layered structures. Multiple wiring layers are stacked vertically with ground layers positioned between signal layers. This dimensional transition allows signal wires to be separated in the vertical dimension while maintaining high horizontal wiring density. The ground layers act as shields between signal layers, effectively reducing crosstalk while preserving the cost advantages of organic interposer materials
Solution Approach 2:
The patent segments the wiring system into distinct functional layers: signal wire layers, ground wire layers, and power layers. This segmentation allows independent optimization of each layer's characteristics. Signal layers can be densely packed for high data throughput, while ground layers provide electromagnetic isolation. The segmentation approach enables the organic interposer to achieve both cost-effectiveness and low crosstalk performance through structured layering rather than relying solely on material properties
4Adaptability or versatility
If wiring length is increased to provide layout flexibility in organic interposers, then layout flexibility is improved, but signal delay variation increases
Solution Approach 1:
The patent employs dynamic impedance control techniques where the characteristic impedance of the wiring system is carefully managed to maintain signal integrity despite variations in wiring length. By controlling impedance matching at connectors and along transmission paths, the patent reduces signal reflections and delay variations. This allows organic interposers to utilize longer wiring lengths for flexible layout while maintaining timing precision required for high-speed serial interfaces
Data Source
AI summary
To provide an inexpensive semiconductor device capable of suppressing the influence by crosstalk. A semiconductor device includes a signal wiring disposed in an organic interposer, an output circuit which is coupled to a first end of the signal wiring and which sets an impedance so as to generate a reflected wave antiphase to a waveform transmitted to the first end and periodically outputs data, and an input circuit which is coupled to a second end of the signal wiring and sets an impedance so as to generate a reflected wave of the same phase as a waveform transmitted to the second end. An average delay of the signal wiring is set to be 1/integer of 2 or more relative to a half of a cycle of the data. A difference between the maximum and minimum values of a delay of a signal at each of other signal wirings disposed in the organic interposer is set to be not greater than the average delay.