Interposer Conductive Posts for Thermal and Electrical Interconnects
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Solution Overview
Problem
High-density electronic modules face challenges in packaging pre-fabricated microelectronic dies with different form factors and thicknesses, and in making efficient electrical and thermal connections, due to limitations in lamination pressure, via diameter, and deep via filling, which restricts design choices and integration density.
Innovation Solution
The method involves encapsulating dies with a bipartite structure including a dielectric layer and an encapsulant, forming posts within cavities for electrical connections, and using these posts to create interposer layers that can be bonded with other components for thermal and electrical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If laser-drilled vias are used for interconnections, then via formation is achievable, but via diameter is limited to approximately 40 μm which restricts die pad sizes and design choices
Solution Approach 1:
The patent replaces laser drilling (a thermal/mechanical process) with electroplating to form conductive posts. This substitution allows for larger via diameters and greater design flexibility, as electroplating can deposit conductive material to any desired thickness and pattern without the diameter limitations of laser drilling.
2Strength
If high pressure is applied for lamination, then dielectric layer lamination is achieved, but dies thinned to less than 100 μm may not survive the high pressure
Solution Approach 1:
The patent forms conductive posts and embeds dies in encapsulant before applying high pressure for dielectric lamination. This preliminary action protects thinned dies from the damaging effects of high pressure, as the encapsulant and post structure provide mechanical support during the lamination process.
3Length of moving object
If deep, high-aspect-ratio vias are formed for interlayer connections, then vertical interconnection is achieved, but reliable and repeatable filling with conductive material becomes difficult
Solution Approach 1:
The patent replaces laser drilling with electroplating to form conductive posts. This substitution eliminates the high-aspect-ratio filling problem entirely, as electroplating builds conductive material from the bottom up in a controlled manner, ensuring reliable and repeatable formation of conductive interconnections regardless of depth.
4Ease of manufacture
If conventional packaging methods are used, then simple assembly is achieved, but efficient electrical contact between modules with different pitches is impossible without custom fabrication
Solution Approach 1:
The patent introduces an interposer layer with conductive posts as an intermediary between modules with different electrical contact pitches. This interposer mediates the connection, allowing modules with incompatible pitches to be interconnected through the posts, which can be configured to match different pitch requirements on either side.
5Adaptability or versatility
If dies with different form factors and thicknesses are packaged together, then application optimization is achieved, but packaging attempts become problematic
Solution Approach 1:
The patent uses individual encapsulant structures for each die, allowing each die to be embedded in its own customized cavity that accommodates its specific form factor and thickness. This local customization approach enables packaging of dies with different characteristics without requiring complex overall packaging structures.
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 approach enables reliable interlayer and intradie connections, allows for greater module thickness, and enhances thermal management by achieving heat-transfer effectiveness greater than 1000, facilitating efficient electrical and thermal interconnections between components.
Implementation Method 1
An encapsulant is injected through the fill hole into the cavity to encapsulate the die
Implementation Method 2
the posts conducting electricity and/or heat through the module
Implementation Method 3
the posts conducting electricity and/or heat through the module
Data Source
AI summary
In accordance with a method for forming an interposer, a fill hole is formed in a first side of a substrate and a cavity is formed in a second side. The cavity is in fluidic communication with the fill hole. A plurality of posts is formed in the cavity, and an encapsulant is injected through the fill hole into the cavity to encapsulate the plurality of posts. In accordance with a method of thermal management, an electronic component and a heat sink are disposed on opposing sides of an interposer that includes a plurality of encapsulated posts.