Substrate Bump Pad Compensation for Coplanar Die Bonding
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Solution Overview
Problem
The non-planar top surface of dielectric structures due to redistribution layers in substrate structures causes level differences, leading to improper connection of semiconductor dies with bump pads, resulting in potential bonding issues.
Innovation Solution
Incorporating a compensation structure, such as an intermediate bump or dummy metal layers, under the bump pads to equalize the thickness and ensure proper alignment and bonding of bump pads with semiconductor dies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redistribution layers are arranged according to layout requirements, then electrical connectivity is improved, but the top surface of dielectric layers becomes non-planar
Solution Approach 1:
The patent applies local quality by introducing compensation structures (dummy metal layers or intermediate bumps) specifically at locations where the top surface deviation exceeds a threshold. This localized approach maintains the overall redistribution layer layout for electrical connectivity while selectively correcting surface planarity issues in specific regions, thus resolving the contradiction between electrical connectivity and surface planarity.
2Reliability
If dielectric layers are stacked to provide insulation, then electrical isolation is improved, but level differences between bump pads increase
Solution Approach 1:
The patent introduces intermediate bumps as mediator structures between the dielectric layers and the bump pads. These intermediate bumps serve as compensatory elements that fill the gaps caused by varying dielectric layer thicknesses, thereby maintaining consistent bump pad levels across the substrate while preserving the stacked dielectric structure for electrical isolation.
3Ease of manufacture
If bump pads are formed at different levels, then connection to redistribution layers is simplified, but bonding with semiconductor dies becomes problematic
Solution Approach 1:
The patent applies preliminary anti-action by pre-compensating for the level differences caused by varying redistribution layer configurations. Compensation structures are formed beforehand to counterbalance the height variations, ensuring that bump pads end up at uniform levels before the bonding process, thus preventing bonding issues while maintaining ease of connection to redistribution layers.
Data Source
AI summary
A substrate structure includes a wiring structure, a first bump pad, a second bump pad and a compensation structure. The wiring structure includes a plurality of redistribution layers. The first bump pad and the second bump pad are bonded to and electrically connected to the wiring structure. An amount of redistribution layers disposed under the first bump pad is greater than an amount of redistribution layers disposed under the second bump pad. The compensation structure is disposed under the second bump pad.