Embedded Trace Substrate for Reduced Bump Pitch and Solder Bridging
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Solution Overview
Problem
As integrated circuit components decrease in size, connection points become crowded, leading to increased risks of electrical shorts and unreliable connections, necessitating a more reliable connection method to address consumer demands for thinner, more functional devices while reducing costs and improving efficiency.
Innovation Solution
An integrated circuit packaging system featuring an embedded trace substrate with traces and bonding sites embedded in a base material, an insulation layer coplanar with the base material's surface, and an integrated circuit die connected to the bonding sites, which prevents solder bridging and reduces bump pitch without increasing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If connection points are placed closer together to reduce device size, then device thickness and size are reduced, but the risk of electrical shorts and cross-connections increases
Solution Approach 1:
The patent transitions from planar surface connections to three-dimensional embedded connections within the substrate. Traces and bonding sites are formed inside the substrate volume rather than on its surface, allowing connection points to be positioned closer together in three-dimensional space while maintaining reliability through the insulating base material that prevents cross-connections.
Solution Approach 2:
The base material serves as an intermediary insulating medium that separates and isolates conductive traces and bonding sites. This intermediary prevents direct contact between adjacent connection points, eliminating the risk of electrical shorts while enabling closer spacing of connection points to reduce device size.
2Ease of manufacture
If traditional surface-mounted traces are used, then manufacturing is simpler, but solder bridging occurs and bump pitch must be increased
Solution Approach 1:
Traces and bonding sites are formed within the substrate before the underfill is applied and before final assembly. This preliminary formation of conductive structures eliminates the need for subsequent soldering operations, preventing solder bridging and allowing for reduced bump pitch without compromising manufacturing simplicity.
Solution Approach 2:
The patent replaces the mechanical soldering process with an embedded trace system where electrical connections are formed through conductive traces within the substrate material. This substitution eliminates the harmful effects of solder bridging while maintaining ease of manufacture through integrated trace formation processes.
3Reliability
If underfill is applied to improve connection reliability, then connection strength is improved, but underfill flow is blocked by surface traces and bonding sites
Solution Approach 1:
By moving traces and bonding sites from the surface to the interior of the substrate, the patent creates a clear path for underfill to flow across the entire surface without obstruction. The underfill can uniformly distribute beneath the device while maintaining contact with the embedded bonding sites, improving both flow characteristics and connection reliability.
Data Source
AI summary
An integrated circuit packaging system, and a method of manufacture thereof, includes: an embedded trace substrate having bonding sites and traces embedded in a base material, an insulation layer on the traces, the insulation layer having a top surface coplanar with the top surface of the base material; and an integrated circuit die connected to the bonding sites.