Cavity-Less Die Encapsulation With Capillary Underfill
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Solution Overview
Problem
Multi-die IC packaging faces challenges due to increased die segregation, power delivery requirements, and stricter routing and alignment tolerances, leading to manufacturing complexity and reliability issues such as solder interconnect failures and volatile surface finishes, which are exacerbated by the use of non-conductive films (NCF) as underfill materials.
Innovation Solution
A microelectronic assembly design that encapsulates bridge dies in a substrate without forming a cavity and eliminates the use of NCF, utilizing organic dielectric materials and capillary underfill to surround solder interconnects, ensuring reliable electrical coupling and simplified manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-conductive film (NCF) is used as underfill material, then solder bump interconnect formation is supported, but inorganic fillers are trapped at the solder to conductive contact interface preventing interconnect formation and creating reliability issues
Solution Approach 1:
The patent removes the NCF underfill material layer from the assembly, eliminating the source of inorganic filler contamination. This extraction of the problematic component directly resolves the issue of filler trapping at the solder interface while maintaining the essential underfill functions through alternative materials.
Solution Approach 2:
The patent changes the material composition from NCF with inorganic fillers to organic-based underfill materials. This parameter change in material chemistry eliminates the filler trapping problem while preserving the mechanical and electrical properties needed for reliable interconnect formation.
2Stability of the object's composition
If NCF material is used as underfill, then surface finish stability is improved, but manufacturing time is limited due to volatile surface finishes and complicated prep processes
Solution Approach 1:
The patent adopts organic-based underfill materials that are easier to apply and cure faster than NCF materials. These materials sacrifice some long-term stability but gain significant manufacturing speed, allowing for quicker processing cycles and reduced manufacturing timeframes.
Solution Approach 2:
The patent changes the surface finish properties by using organic materials with different curing characteristics. This parameter change enables faster curing times and reduces the volatility issues associated with NCF, thereby extending the effective manufacturing timeframe.
3Ease of manufacture
If cavity formation is used to embed bridge die, then die embedding is achieved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent eliminates the cavity formation step from the manufacturing process. By removing this complex structural feature, the patent simplifies the overall manufacturing process while still achieving the essential function of bridge die embedding through direct placement and underfill encapsulation.
Solution Approach 2:
Instead of creating a cavity and then embedding the die, the patent inverts the approach by placing the die first and then forming the underfill structure around it. This inversion eliminates the need for complex cavity formation while achieving the same embedding result.
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 reduces manufacturing complexity and cost while enhancing reliability by eliminating NCF-related failures and volatile surface finishes, facilitating efficient signal communication between dies.
Implementation Method 1
the interconnects include solder and are surrounded by a capillary underfill material
Data Source
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AI summary
Microelectronic assemblies, related devices and methods, are disclosed herein. In some embodiments, a microelectronic assembly may include a substrate having a material and conductive pathways through the material, wherein the material includes an organic dielectric material; and a microelectronic component having a first surface and an opposing second surface, wherein the first surface of the microelectronic component is electrically coupled to the conductive pathways in the material by interconnects, wherein the interconnects include solder and are surrounded by a capillary underfill material, and wherein the microelectronic component and the capillary underfill material are surrounded by the material of the substrate.