Silicon Interposer for Hybrid Laser Thermo-Mechanical Stress
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Solution Overview
Problem
Current optoelectronic device modules with hybrid silicon lasers face reliability issues due to thermal and mechanical stress caused by coefficient of thermal expansion mismatches between the silicon transmitter die and the substrate, leading to potential damage and reduced long-term reliability.
Innovation Solution
Incorporating a silicon interposer between the hybrid silicon laser and the substrate, which electrically connects the silicon photonics transmitter die to the substrate through through-silicon vias and thermal bridges, eliminating nonconductive encapsulation and reducing thermo-mechanical stress by matching the coefficient of thermal expansion between the die and the interposer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a hybrid silicon laser is integrated on a silicon platform, then bandwidth exceeding 100 Gbps is achieved, but thermal and mechanical stress is generated due to coefficient of thermal expansion mismatches between the silicon transmitter die and substrate
Solution Approach 1:
A silicon interposer is introduced as an intermediary component between the silicon photonics transmitter die and the substrate. The interposer has a coefficient of thermal expansion that matches the silicon die, serving as a thermal and mechanical buffer that eliminates stress while maintaining the high-bandwidth performance of the integrated optical module
Solution Approach 2:
The coefficient of thermal expansion parameter is matched between the silicon interposer and the silicon photonics transmitter die. By changing the material parameter (selecting silicon for the interposer rather than using the substrate directly), the thermal and mechanical stress is eliminated while preserving the high bandwidth capability
2Object-affected harmful factors
If nonconductive encapsulation is used to protect the hybrid silicon laser, then mechanical protection is provided, but thermal and mechanical stress is increased due to CTE mismatch
Solution Approach 1:
The silicon interposer acts as a mediator between the hybrid silicon laser and the nonconductive encapsulation/substrate. It provides a thermal and mechanical buffer zone that protects the laser from stress while allowing the encapsulation to perform its protective function without transmitting harmful stress
Solution Approach 2:
The interposer creates a homogeneous thermal and mechanical interface between the silicon die and the substrate by matching the coefficient of thermal expansion. This homogeneity eliminates the stress concentration that would otherwise occur at the interface between materials with different CTE values
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 enhances the long-term reliability of the optoelectronic device module by maintaining electrical, thermal, and optical paths while protecting the hybrid silicon laser from thermal and mechanical stress, ensuring stable operation and reduced form factor.
Implementation Method 1
electrically connects the silicon photonics transmitter die to the substrate through through-silicon vias
Implementation Method 2
thermal bridges, eliminating nonconductive encapsulation and reducing thermo-mechanical stress
Implementation Method 3
reducing thermo-mechanical stress by matching the coefficient of thermal expansion between the die and the interposer
Data Source
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AI summary
Optoelectronic device modules having a silicon photonics transmitter die connected to a silicon interposer are described. In an example, the optoelectronic device module includes a silicon photonics transmitter die connected to a silicon interposer, and the silicon interposer is disposed between the silicon photonics transmitter die and a substrate. The silicon interposer provides an electrical interconnect between the silicon photonics transmitter die and the substrate, and reduces a likelihood that a hybrid silicon laser on the silicon photonics transmitter die will be damaged during module operation.