Molded EMIB Bridge with Graded CTE for Thermomechanical Stability
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Solution Overview
Problem
Embedded multi-die interconnect bridges (EMIBs) face thermomechanical issues such as heat-induced stresses, warpage, and delamination due to the mismatch in coefficient of thermal expansion (CTE) between the silicon bridge and the substrate, limiting the size of the embedded bridge and restricting high-speed input/output signaling.
Innovation Solution
A molded fine line and spaced (FLS) interconnect bridge with graded CTEs is employed to minimize CTE mismatch, using low-cost substrate and molded embedded pane-level ball (EPLB) grid array packaging processes, allowing for wider design flexibility and improved thermal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a silicon bridge is used in EMIB, then high-density die-to-die connections are enabled, but thermomechanical issues such as heat induced stresses, warpage, and delamination occur due to CTE mismatch
Solution Approach 1:
The patent changes the material parameter (CTE) of the bridge from silicon (low CTE) to an organic material with CTE matched to the substrate. This parameter change eliminates the CTE mismatch problem while maintaining the high-density interconnect capability, thereby resolving the contradiction between manufacturing precision and thermomechanical reliability
Solution Approach 2:
The patent uses composite material structures including the organic bridge material integrated with the organic substrate, and employs multiple dielectric layers with conductive vias to create a composite interconnect system. This composite approach allows for CTE matching while achieving high-density connections, resolving the technical contradiction
2Productivity
If the bridge size is increased to enhance performance, then more I/O signals can be supported, but thermomechanical stresses and warpage increase due to CTE mismatch
Solution Approach 1:
By changing the CTE parameter of the bridge material to match the substrate, the patent enables larger bridge sizes to be used without increasing thermomechanical stresses. This allows higher I/O signaling capacity to be achieved without the harmful thermomechanical effects that would normally limit bridge size
Solution Approach 2:
The patent applies preliminary anti-action by pre-matching the CTE of the bridge material to the substrate before assembly. This preliminary design choice prevents thermomechanical stresses and warpage from developing during subsequent thermal cycles, enabling larger bridge sizes for enhanced productivity
3Ease of manufacture
If silicon design rules are used for the bridge, then silicon manufacturing processes can be applied, but creation of metal reference planes is restricted which limits high-speed signaling
Solution Approach 1:
The patent changes the material system from silicon-based to organic-based, which changes the design rules and manufacturing parameters. This allows metal reference planes to be created using organic substrate technologies, enabling high-speed signaling while maintaining ease of manufacture through established organic PCB and substrate processes
Solution Approach 2:
The patent replaces expensive silicon interposer technology with lower-cost organic substrate technology. This substitution achieves the same high-density interconnect function at lower cost and with greater design flexibility for metal reference planes, resolving the contradiction between manufacturing ease and signaling adaptability
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
The solution effectively balances CTE mismatch, reduces thermomechanical stresses, and enables larger embedded bridge sizes, while providing flexibility for high-speed signaling, thus enhancing the performance and reliability of EMIB substrates.
Implementation Method 1
thermomechanical issues such as heat induced stresses, warpage, delamination, etc both within the substrate as well as post flip chip attachment
Data Source
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AI summary
Disclosed is an embedded multi-die interconnect bridge (EMIB) substrate. The EMIB substrate can comprise an organic substrate, a bridge embedded in the organic substrate and a plurality of routing layers. The plurality of routing layers can be embedded within the bridge. Each routing layer can have a plurality of traces. Each of the plurality of routing layers can have a coefficient of thermal expansion (CTE) that varies from an adjacent routing layer.