LIDAR Circuit Module TSV Layout for CTE Mismatch Relief
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Solution Overview
Problem
The mismatch in coefficient of thermal expansion (CTE) between III-V semiconductor materials and silicon substrates in LIDAR sensor systems leads to mechanical stress and potential defects during thermal cycling, affecting the reliability and yield of the bonding interface.
Innovation Solution
Incorporating an array of conductive through-silicon vias (TSVs) in a specific portion of the silicon substrate to adjust the composite CTE, reducing mechanical stress and improving the coupling between III-V semiconductor and silicon substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If III-V semiconductor substrate is coupled to silicon substrate, then optical device performance is improved, but mechanical stress and defects occur due to CTE mismatch
Solution Approach 1:
The patent modifies the physical parameters of the silicon substrate by incorporating through-silicon vias (TSVs) with specific dimensions, materials, and distributions. These TSVs change the effective CTE of the silicon substrate to better match the III-V semiconductor substrate, thereby reducing thermal stress during thermal cycling while maintaining bonding interface reliability
Solution Approach 2:
The patent creates a composite structure by integrating TSVs (made of different materials such as copper, tungsten, or aluminum) into the silicon substrate. This composite approach allows the silicon substrate to achieve an effective CTE that matches the III-V semiconductor material, reducing mechanical stress at the bonding interface during thermal expansion and contraction
2Reliability
If array of conductive TSVs is added to silicon substrate, then mechanical stress is reduced, but device complexity increases
Solution Approach 1:
The patent applies TSVs locally in specific regions of the silicon substrate where thermal stress is most critical, rather than uniformly across the entire substrate. This localized approach reduces mechanical stress at the bonding interface while minimizing the overall increase in device complexity and maintaining manufacturing feasibility
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
Enhances the robustness and reliability of the bonding interface by minimizing mechanical stress, thereby improving the process yield and performance of LIDAR sensor systems.
Implementation Method 1
The mismatch in coefficient of thermal expansion (CTE) between III-V semiconductor materials and silicon substrates in LIDAR sensor systems leads to mechanical stress and potential defects during thermal cycling
Data Source
AI summary
A light detection and ranging (LIDAR) sensor system includes a circuit module. The circuit module includes a silicon substrate having a first thermal feature. The circuit module includes a III-V semiconductor substrate coupled to the silicon substrate, the III-V semiconductor substrate having a second thermal feature. The circuit board includes an optical device coupled to the III-V semiconductor substrate, the optical device configured to output a transmit beam. The circuit module further includes a plurality of vias disposed in a particular portion of the silicon substrate, where the particular portion corresponds to the III-V semiconductor substrate, at least one of the plurality of vias having a third thermal feature. The LIDAR system further includes a scanner configured to direct the transmit beam to an environment of the vehicle.