Passive Optical Interposer Waveguides for Memory Wall Bottlenecks

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Solution Overview

Problem

The memory wall phenomenon, which refers to the discrepancy between the operational speed of processing units and memory latency, poses a bottleneck in high-performance computing and artificial intelligence processing, limiting overall system performance and efficiency.

Innovation Solution

Optical links are established through waveguides within a passive optical interposer to connect processing units and memories, allowing for faster and more efficient data exchange, reducing latency, and integrating external memories into the cache system of processing units.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If optical links are established through waveguides to connect processing units and memories, then data transfer speed and efficiency are improved, but device complexity and manufacturing difficulty increase

Engineering Contradiction:

Improvedata transfer speedVSAvoiddevice complexity

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

A passive optical interposer is introduced as an intermediary component between processing units and memory devices. The interposer contains waveguides that facilitate optical data transfer, eliminating the need for complex active optical components in each processor while achieving high-speed communication through standardized interfaces.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Electrical signal transmission through traditional PCB traces is replaced with optical signal transmission through waveguides. This substitution enables higher data transfer speeds and reduces electromagnetic interference, while the passive nature of the waveguide structure simplifies the overall system architecture compared to active optical components.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Loss of time

If optical waveguides are integrated into the interposer, then memory latency is reduced, but manufacturing precision requirements increase

Engineering Contradiction:

Improvememory latencyVSAvoidwaveguide alignment precision

Core Design Contradiction:

Loss of timeVSManufacturing precision

Solution Approach 1:

Waveguide structures are pre-formed in the passive optical interposer during semiconductor fabrication processes before final assembly. This preliminary formation ensures precise alignment and coupling between waveguides and photonic components, eliminating the need for complex post-fabrication alignment procedures.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The waveguide structures are merged with the interposer substrate in a single integrated component rather than being separate elements requiring precise assembly. This integration approach, combined with standardized interface designs, reduces manufacturing precision requirements while maintaining low latency performance.

Inventive Principle:

Principle #5Merging (Combining)

3Productivity

If external memories are integrated into the cache system through optical links, then system performance is improved, but power consumption and heat generation increase

Engineering Contradiction:

Improvesystem performanceVSAvoidpower consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

Electrical signal transmission is replaced with optical signal transmission through waveguides. Optical transmission consumes less power for high-speed data transfer and generates less heat compared to electrical signals, enabling external memories to be integrated into the cache system without proportional increases in power consumption or heat generation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution reduces memory latency and enhances data transfer efficiency, providing a sustainable path for high-performance computing systems without proportional increases in power consumption or heat generation, thereby improving system performance and scalability.

Implementation Method 1

Optical links are established through waveguides within a passive optical interposer to connect processing units and memories

Methodology Applied

Scientific EffectOptical waveguide transmission: Waveguide (optics)

Data Source

PatentUS20250239578A1Optical connector unit for a photonic assembly and methods for forming the same

Publication Date: 2025.07.24 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A passive optical interposer is provided, which includes interposer dielectric material layers having formed therein interposer waveguides and interposer bonding pads is provided. A first assembly is provided, which includes a first semiconductor die and at least one first photonic die including first photonic devices and first waveguides. A second assembly is provided, which includes a second semiconductor die and at least one second photonic die including second photonic devices and second waveguides. The first assembly is attached to the passive optical interposer. A subset of the first waveguides are optically coupled to a first subset of the interposer waveguides through evanescent coupling. The second assembly is attached to the passive optical interposer. A subset of the second waveguides are optically coupled to a second subset of the interposer waveguides through evanescent coupling. The first semiconductor die and the second semiconductor die are coupled through optical signal transmission paths.