Microelectronic Assemblies with Reinforcing Collars on Connectors
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Solution Overview
Problem
Current microelectronic package structures face challenges in achieving compact, high-speed interconnections between complex chips with numerous input and output connections, as existing solutions do not adequately address the need for short, low-impedance interconnects that do not increase assembly size, especially in portable devices and data servers.
Innovation Solution
The proposed microelectronic assembly features first and second support elements with conductive connectors projecting above their surfaces, encapsulated to maintain connector height and prevent expansion, allowing for stacked chip arrangements with vertical interconnects that provide a desirable standoff height while being tightly packed horizontally, using conductive masses and solid metal posts with encapsulation to ensure electrical coupling and mechanical reinforcement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If connectors are made taller to provide adequate standoff height for vertical interconnects, then electrical coupling between stacked chips is improved, but the horizontal space required increases, reducing packing density
Solution Approach 1:
The encapsulation material is flowed into and around the connectors, nesting the connectors within the encapsulation matrix. This allows tall connectors to be accommodated without increasing horizontal footprint, as the encapsulation conforms to the connector geometry and provides structural support, resolving the contradiction between connector height and packing density
Solution Approach 2:
The solution transitions from a two-dimensional planar layout to a three-dimensional vertical stacking architecture. Connectors extend vertically through the encapsulation to provide standoff height for electrical coupling, while the encapsulation contains these vertical extensions within a compact horizontal footprint, enabling dense packing in the horizontal plane while maintaining adequate vertical separation
2Ease of manufacture
If connectors are allowed to expand during assembly, then ease of alignment and joining is improved, but manufacturing precision of connector position and height deteriorates
Solution Approach 1:
The encapsulation material is applied beforehand to surround and support the connectors during the assembly process. This pre-formed encapsulation structure prevents connectors from expanding or shifting during joining operations, maintaining manufacturing precision while still allowing adequate tolerance for alignment through the compliant encapsulation matrix
Solution Approach 2:
The encapsulation material acts as an intermediary between the connectors and the external environment. It provides a compliant medium that allows for thermal expansion and manufacturing tolerances while maintaining precise connector positioning and height, resolving the contradiction between ease of assembly and manufacturing precision
3Volume of stationary object
If chip packages are stacked closer together to reduce assembly size, then volume efficiency is improved, but heat dissipation capability deteriorates due to reduced thermal pathways
Solution Approach 1:
The encapsulation material is formulated with specific thermal conductivity properties to enable efficient heat dissipation through the vertical interconnect region. By optimizing the local thermal properties of the encapsulation in the vertical pathway, heat can be effectively conducted away from stacked chips even when packages are closely spaced, resolving the contradiction between compact volume and heat dissipation capability
Data Source
AI summary
A microelectronic assembly or package can include first and second support elements and a microelectronic element between inwardly facing surfaces of the support elements. First connectors and second connectors such as solder balls, metal posts, stud bumps, or the like face inwardly from the respective support elements and are aligned with and electrically coupled with one another in columns. Dielectric reinforcing collars are provided on outer surfaces of the first connectors, second connectors or both, and an encapsulation separates pairs of coupled connectors from one another and may fill spaces between support elements.