Semiconductor Package Interconnect Using ACF for Ultra-Fine Pitch Bonding
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Solution Overview
Problem
The hybrid bonding process for stacked semiconductor devices with ultra-fine pitch requires high-precision equipment and precise surface roughness management to prevent connection defects, which is challenging and costly.
Innovation Solution
The use of an anisotropic conductive film (ACF) with conductive particles positioned between connection members and bonding pads, forming an interconnection structure that eliminates the need for high-precision equipment and precise surface roughness management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hybrid bonding process is used for ultra-fine pitch stacked semiconductor devices, then connection reliability is improved, but manufacturing complexity and cost increase due to requiring high-precision equipment and strict surface roughness control
Solution Approach 1:
The patent introduces a nonconductive film with embedded conductive particles as an intermediary bonding layer between semiconductor dies. This ACF layer mediates the bonding process by providing pre-positioned conductive elements that facilitate electrical connection without requiring the ultra-fine precision of hybrid bonding, thus maintaining connection reliability while reducing manufacturing complexity
Solution Approach 2:
The patent changes the bonding parameters by transitioning from direct die-to-die hybrid bonding to bonding through an ACF layer. This parameter change allows bonding at higher surface roughness values (relaxing the strict surface finish requirements) while maintaining electrical connection quality through the conductive particles embedded in the nonconductive film
2Reliability
If hybrid bonding process is used for ultra-fine pitch stacked semiconductor devices, then connection reliability is improved, but equipment cost increases due to requiring high-precision equipment
Solution Approach 1:
The ACF layer serves as a mediator that enables bonding with standard equipment rather than requiring expensive high-precision hybrid bonding equipment. The pre-formed conductive particles in the nonconductive film provide the necessary electrical connection capability without demanding ultra-fine positioning accuracy
Solution Approach 2:
The patent uses a consumable ACF bonding layer that is applied and then remains as part of the final structure. This disposable-like approach replaces expensive reusable high-precision equipment with a cheaper material-based solution that achieves the same functional outcome
3Reliability
If surface roughness is controlled to 10 Å or less for hybrid bonding, then connection defects are prevented, but manufacturing difficulty and cost increase
Solution Approach 1:
The patent changes the surface roughness parameter requirement by introducing the ACF layer. The nonconductive film with embedded conductive particles compensates for surface irregularities, allowing bonding to proceed successfully at higher roughness values (e.g., 1-10 nm RMS) without increasing connection defect rates
Solution Approach 2:
The ACF provides local electrical connection quality through conductive particles positioned at specific locations within the nonconductive film. This local quality approach ensures reliable electrical paths even when the overall bonding surface has higher roughness, as the conductive particles create localized low-resistance paths
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
Enables reliable electrical connections without connection defects, even at ultra-fine pitches, reducing the need for expensive high-precision equipment and ensuring consistent bonding quality.
Implementation Method 1
The conductive particles may electrically connect each of the connection members to the corresponding bonding pad of the bonding pads
Implementation Method 2
an anisotropic conductive film (ACF) may be disposed between the first semiconductor die and the second semiconductor die
Data Source
AI summary
A semiconductor package according to an embodiment includes a first semiconductor die, a plurality of bonding pads on the first semiconductor die, a plurality of connection members on the plurality of bonding pads, wherein each connection member of the plurality of connection members is disposed on a corresponding bonding pad of the plurality of bonding pads, a second semiconductor die on the plurality of connection members, and an anisotropic conductive film between the first semiconductor die and the second semiconductor die, and between the plurality of bonding pads and the plurality of connection members, including an insulating film, and conductive particles inside the insulating film, wherein the conductive particles are positioned between each of the plurality of connection members and the corresponding bonding pad of the plurality of bonding pads.