Reducing CTE Mismatch in LIDAR Sensors with TSVs
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Summary
Problems
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 defects, such as cracks and delamination, under thermal cycling conditions, affecting the reliability and yield of the bonding interface.
Innovation solutions
Incorporating an array of conductive through-silicon vias (TSVs) in the silicon substrate to adjust the composite CTE of the silicon substrate to match that of the III-V semiconductor substrate, reducing mechanical stress and improving the bonding interface reliability.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If III-V semiconductor substrate is bonded to silicon substrate, then optical device functionality is achieved, but mechanical stress and defects occur due to CTE mismatch
Why choose this principle:
The patent modifies the physical parameters of the silicon substrate by incorporating through-silicon vias (TSVs) filled with materials having different CTE values. This changes the effective CTE of the silicon substrate to better match the III-V semiconductor substrate, thereby reducing thermal stress at the bonding interface during thermal cycling.
Principle concept:
If III-V semiconductor substrate is bonded to silicon substrate, then optical device functionality is achieved, but mechanical stress and defects occur due to CTE mismatch
Why choose this principle:
The patent creates a composite structure by integrating TSVs within the silicon substrate. The TSVs are filled with materials such as copper, tungsten, or other metals that have higher CTE values than silicon, forming a composite material system whose effective CTE can be tuned to match the III-V semiconductor substrate.
Application Domain
Data Source
AI summary:
Incorporating an array of conductive through-silicon vias (TSVs) in the silicon substrate to adjust the composite CTE of the silicon substrate to match that of the III-V semiconductor substrate, reducing mechanical stress and improving the bonding interface reliability.
Abstract
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.