Redundant Micro-bump Placement on Interposer Bond Pads
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The use of redundant micro-bumps in flip-chip bonding increases area overhead, reducing the number of input/output connections between IC dice and an interposer, which limits the density and performance of integrated circuit packages.
Innovation Solution
Placing redundant micro-bumps on the same bond pads on the interposer instead of separate pads, increasing micro-bump density and reducing area overhead while maintaining improved bonding yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant micro-bumps are added to each pad on the interposer to improve bonding yield, then bonding yield is improved, but area overhead increases linearly with the number of redundant micro-bumps
Solution Approach 1:
Multiple micro-bumps (including redundant ones) are merged onto the same bond pad location on the interposer. Instead of distributing each micro-bump to a separate pad, the patent combines multiple micro-bumps at each bond pad site, allowing redundant micro-bumps to share the same pad footprint. This merging approach maintains bonding yield improvement while preventing linear area overhead increase.
Solution Approach 2:
Each bond pad on the interposer is designed to serve multiple functions by accommodating multiple micro-bumps simultaneously. The bond pad structure becomes universal, capable of supporting both primary connection micro-bumps and redundant micro-bumps, as well as connecting to multiple die pads. This multi-functionality allows the same pad structure to handle redundancy without requiring additional dedicated pads for each redundant connection.
2Reliability
If redundant micro-bumps are used for each connection between the interposer and the IC dice, then bonding yield is improved, but the number of input/output connections that can be formed decreases
Solution Approach 1:
The patent merges multiple micro-bump functions into a single bond pad location. By combining redundant micro-bumps with primary connection micro-bumps at the same pad site, the system achieves both reliability improvement and maintains high I/O connection density. This merging prevents the need to allocate separate pads for redundancy, thereby preserving the number of available I/O connections.
Solution Approach 2:
The patent transitions from a one-to-one mapping between pads and micro-bumps to a many-to-one relationship where multiple micro-bumps map to a single pad location. This dimensional change in the mapping relationship allows redundant micro-bumps to be accommodated without increasing the two-dimensional pad layout area, effectively adding redundancy in a different organizational dimension rather than expanding the physical pad array.
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 configuration allows for a higher number and density of input/output connections between the IC dice and the interposer, enhancing the performance and efficiency of integrated circuit packages without increasing area overhead.
Implementation Method 1
One technique for connecting the IC dice to the interposer is thermal compression bonding. A single solder bump (e.g., a micro-bump) is deposited on each bond pad on the interposer to form the bonds between the IC die and the interposer. The IC die is pressed to the interposer by a thermal compression bonding tool and heat is applied to fuse the IC die to the interposer.
Data Source
AI summary
A semiconductor device is provided that includes a substrate having opposing first and second surfaces and an interconnect structure extending between the first and second surfaces. A plurality of bond pads are located on the first surface of the substrate and the bond pads are electrically connected to the interconnect structure. The bond pads each have two or more micro-bumps, with the two or more micro-bumps on each bond pad being arranged to electrically connect the bond pad to one die pad of a semiconductor die. A plurality of external contacts are located on the second surface of the substrate and the external contacts are electrically connected to the interconnect structure.