NTE Material Interconnects for Semiconductor Substrate Integrity
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Solution Overview
Problem
Conventional semiconductor interconnect materials, such as metals, expand and contract more than the substrate materials in response to temperature changes, leading to stress and potential substrate cracking, device malfunction, and yield loss due to their higher coefficient of thermal expansion (CTE) compared to silicon.
Innovation Solution
Incorporating negative thermal expansion (NTE) materials, like zirconium tungstate, into semiconductor device interconnects, such as through-silicon vias (TSVs), which contract with increasing temperature, creating an open space for the conductive materials to expand into, thereby reducing stress and preventing substrate cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional metal interconnect materials are used, then electrical conductivity is achieved, but thermal stress and substrate cracking occur due to higher CTE compared to silicon substrate
Solution Approach 1:
The patent changes the thermal expansion parameter by incorporating NTE materials with negative coefficient of thermal expansion into the interconnect structure. This creates a composite material system where the overall CTE can be tuned to match the silicon substrate, eliminating thermal stress during temperature cycling.
Solution Approach 2:
The patent uses composite interconnect structures combining conventional conductive materials with NTE materials. This composite approach allows the structure to maintain electrical conductivity while the NTE component compensates for thermal expansion differences, preventing substrate cracking.
2Reliability
If NTE materials are incorporated into interconnects, then thermal stress is reduced and substrate cracking is prevented, but device complexity increases
Solution Approach 1:
The patent implements NTE materials in nested configurations within the interconnect structure, such as coating NTE material on conductive cores or embedding NTE particles within conductive matrices. This nesting approach maintains functional integration while achieving CTE matching.
Solution Approach 2:
The patent applies NTE materials selectively in specific regions of the interconnect structure where thermal stress concentration occurs, rather than uniformly throughout. This localized application reduces the amount of NTE material needed and simplifies the overall device architecture.
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
The use of NTE materials in interconnects allows for a composite CTE that can be customized to match or exceed the substrate's CTE, reducing thermal stress and preventing cracking, thereby enhancing the reliability and yield of semiconductor devices.
Implementation Method 1
Incorporating negative thermal expansion (NTE) materials, like zirconium tungstate, into semiconductor device interconnects, such as through-silicon vias (TSVs), which contract with increasing temperature
Implementation Method 2
Conventional semiconductor interconnect materials, such as metals, expand and contract more than the substrate materials in response to temperature changes, leading to stress and potential substrate cracking, device malfunction, and yield loss due to their higher coefficient of thermal expansion (CTE) compared to silicon
Data Source
Figure 1A~1C
Figure 2A~2C
Figure 3A~3B
AI summary
Semiconductor devices having interconnects incorporating negative expansion (NTE) materials are disclosed herein. In one embodiment a semiconductor device includes a substrate having an opening that extends at least partially through the substrate. A conductive material having a positive coefficient of thermal expansion (CTE) partially fills the opening. A negative thermal expansion (NTE) having a negative CTE also partially fills the opening. In one embodiment, the conductive material includes copper and the NTE material includes zirconium tungstate.