Bridge Chip Multi-Chip Assembly for Stress-Relieved Interconnects
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Solution Overview
Problem
Current multi-chip interconnection technologies, such as EMIB structures, face assembly issues due to mechanical stresses around joints between chips and organic substrates, leading to packaging yield degradation.
Innovation Solution
A method for fabricating a bridged multi-chip assembly structure that involves arranging chips on a carrier substrate, depositing molding material to rigidly fix them, and bonding a bridge chip, which relieves stress by ensuring the chips are firmly connected, eliminating the need for recesses or trenches in the organic substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If EMIB structure is used to interconnect chips, then high-density interconnection is achieved, but mechanical stresses around joints cause assembly failure and yield degradation
Solution Approach 1:
The patent introduces a bridge chip as an intermediary component between the organic substrate and the functional chips. This bridge chip absorbs and distributes the mechanical stresses that arise from coefficient of thermal expansion differences, preventing stress concentration at the joints between chips and the organic substrate. The bridge chip acts as a stress-relieving mediator that maintains joint integrity during assembly and operation.
Solution Approach 2:
The patent employs a composite structure consisting of multiple materials with different properties: the organic substrate, the bridge chip, and the functional chips are combined in a specific configuration. This composite arrangement allows each material to contribute its advantageous properties while the overall structure compensates for the weaknesses of individual components, particularly regarding thermal expansion mismatch and stress distribution.
2Ease of manufacture
If recesses or trenches are formed in organic substrate to accommodate bridge chip, then interference is avoided, but fabrication cost increases
Solution Approach 1:
The patent resolves the spatial interference problem by transitioning from a two-dimensional planar arrangement to a three-dimensional stacked configuration. The bridge chip is positioned in the vertical dimension above the organic substrate, connected via bumps, rather than requiring lateral recesses or trenches. This dimensional change eliminates the need for complex substrate modifications while avoiding interference between components.
Solution Approach 2:
The patent performs preliminary bonding of bumps to the bridge chip and functional chips before final assembly onto the organic substrate. This preliminary action ensures proper positioning and electrical connection are established in advance, allowing the bridge chip to be integrated without requiring post-assembly modifications to the organic substrate such as recesses or trenches, thereby simplifying the overall fabrication process.
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 improves manufacturing yield and reduces fabrication costs by minimizing mechanical stress and eliminating the need for specialized substrate design, while enabling high-performance chip connections.
Implementation Method 1
relieving stress generated around joints between the chip and the bridge chip by rigidly fixing the plurality of chips
Implementation Method 2
bonding a bridge chip to corresponding sets of terminals of at least two chips of the plurality of chips fixed by the molding material
Data Source
AI summary
A method of fabricating a bridged multi-chip assembly structure includes providing a carrier substrate. The method further includes arranging a plurality of chips on the carrier substrate in a predetermined layout. Each chip has a front surface including a set of terminals formed thereon. The method further includes depositing a molding material between the plurality of chips and on the carrier substrate. The method further includes removing the carrier substrate from the plurality of chips fixed by the molding material. The method further includes bonding a bridge chip to corresponding sets of terminals of at least two chips of the plurality of chips fixed by the molding material.