Conformal Power Delivery Structures for Semiconductor Packages
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Solution Overview
Problem
Power delivery in semiconductor packages using parallel power planes results in increased lateral resistance due to perforations, which can be up to twice that of a solid plane, and finer lithography techniques only partially mitigate this issue by increasing metal layer thickness.
Innovation Solution
A conformal power delivery structure is implemented, where a top power plane layer is deposited onto a lower power plane layer using a cold spray process, with a thin dielectric material in between, allowing for self-aligned, ultra-small anti-pads and improved lateral electrical resistance and thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If parallel power planes are used with through vias to connect devices, then power delivery is achieved, but lateral resistance increases significantly (up to 2× compared to solid plane)
Solution Approach 1:
The patent implements nested power planes where a first power plane is formed within recesses of a second power plane, creating a conformal nested structure. This nesting allows both power planes to be utilized effectively without requiring large anti-pads, thereby reducing lateral resistance while maintaining power delivery capability.
Solution Approach 2:
The patent transitions from traditional parallel power planes to a conformal nested arrangement where planes are positioned in recesses, effectively utilizing the vertical dimension and surface topology to reduce the impact of anti-pads on lateral resistance.
2Manufacturing precision
If anti-pads are made smaller through improved lithography and alignment techniques, then lateral resistance is reduced, but metal layers must be thinner which increases lateral resistance
Solution Approach 1:
By nesting the first power plane within recesses of the second power plane, the structure allows for smaller anti-pads without requiring thinner metal layers, as the nested configuration provides structural support and electrical continuity despite reduced anti-pad size.
3Loss of energy
If conformal power planes are used with thin dielectric material, then lateral resistance and inductance are reduced, but manufacturing complexity increases
Solution Approach 1:
The recesses in the second power plane are formed in advance before depositing the first power plane, allowing the thin dielectric material to be conformally deposited in a controlled manner, which simplifies the overall manufacturing process despite the conformal structure.
Solution Approach 2:
The conformal deposition process automatically conforms to the recess geometry, with the thin dielectric material self-aligning to the surface topology, reducing the need for additional alignment steps and complex manufacturing procedures.
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 configuration significantly reduces lateral resistance and improves transient response characteristics while maintaining or reducing the volume of power planes compared to traditional parallel structures.
Implementation Method 1
The conformal power delivery structure may include a top/second power plane layer deposited (e.g., via a cold spray deposition process) onto a lower/first power plane layer
Data Source
AI summary
In one embodiment, a conformal power delivery structure includes a first electrically conductive layer comprising metal. The first electrically conductive layer defines one or more recesses, and the conformal power delivery structure also includes a second electrically conductive layer comprising metal that is at least partially within the recesses of the first electrically conductive layer. The second electrically conductive layer has a lower surface that generally conforms with the upper surface of the first electrically conductive layer. The conformal power delivery structure further includes a dielectric material between the surfaces of the first electrically conductive layer and the second electrically conductive layer that conform with one another.