Symmetric Dummy Bridge Layout for FLI Alignment Stability
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Solution Overview
Problem
Advanced packaging architectures face die edge misalignment issues due to non-uniform thermal expansion during thermocompression bonding, which is not attributed to tool placement offset or bump compensation, and is exacerbated by the presence of embedded bridge dies.
Innovation Solution
Incorporating dummy bridges with symmetrically positioned conductive routing or as monolithic bodies, matching the material and dimensions of embedded bridges, to balance thermal expansion and mitigate misalignment by placing them proximate to edges or corners of the package substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If bridge dies are embedded in the package substrate to couple overlying dies, then die coupling functionality is improved, but die edge misalignment occurs during thermocompression bonding
Solution Approach 1:
The patent applies asymmetry by introducing dummy bridges that create a symmetrical layout pattern. The dummy bridges are positioned symmetrically with respect to the center of the package substrate, balancing the asymmetrical thermal expansion effects caused by the functional bridge dies. This symmetrical arrangement compensates for the misalignment forces and improves die edge alignment during thermocompression bonding.
2Adaptability or versatility
If asymmetric bridge die layout is used to accommodate functional requirements, then device functionality is improved, but thermal expansion asymmetry causes die edge misalignment
Solution Approach 1:
The dummy bridges act as counterweights to the functional bridge dies. By positioning dummy bridges symmetrically opposite to the functional bridges, the patent creates a balanced thermal expansion profile. The dummy bridges compensate for the asymmetrical thermal forces generated by the functional bridges, stabilizing the overall thermal behavior and preventing die edge misalignment during temperature cycling.
3Manufacturing precision
If dummy bridges are added to balance thermal expansion, then alignment precision is improved, but device complexity increases
Solution Approach 1:
The dummy bridges are simplified copies of the functional bridge dies. They replicate the basic structural form and material composition of the functional bridges but omit the complex conductive routing and electrical connections. This copying approach allows the dummy bridges to provide thermal balancing functionality without adding significant device complexity, as they can be manufactured using the same processes as the functional bridges.
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 addition of dummy bridges improves first-level interconnect alignment by balancing thermal expansion, reducing die edge misalignment and maintaining die area for functioning circuitry.
Implementation Method 1
asymmetrical substrate thermal expansion during fast heating/cooling cycles during TCB may contribute to DEM problems
Data Source
AI summary
Embodiments disclosed herein include package architectures. In an embodiment, the package architecture comprises a package substrate, a first bridge in the package substrate, where the first bridge includes conductive routing, and a second bridge in the package substrate. In an embodiment, the package architecture further comprises a third bridge in the package substrate, where the second bridge and the third bridge are positioned symmetrically about the first bridge.