Dual-Die IC Module Bonding via Substrate Heat Conduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for stacking integrated circuits are limited by the inability to bond die on opposite sides of a substrate using thermocompression or thermosonic bonding, leading to complex structures and scalability issues, while also compromising signal integrity and manufacturing costs.
Innovation Solution
A system and method for bonding multiple integrated circuit dice on opposite sides of a redistribution substrate using thermocompression or thermosonic bonding, with techniques such as bonding pads between the substrate and die, or using conductive vias, and applying compression forces and ultrasonic vibrations with heating to improve signal integrity and reduce manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermocompression or thermosonic bonding is used to bond die on opposite sides of a substrate, then signal integrity is improved and manufacturing costs are reduced, but the ability to bond die on opposite sides was previously impossible with these processes
Solution Approach 1:
The patent extends the bonding process from single-side to dual-side by utilizing the third dimension (through-substrate connectivity). Conductive vias are formed through the substrate to enable electrical and mechanical connection between die mounted on opposite faces, transforming a 2D bonding process into a 3D integrated structure.
Solution Approach 2:
The substrate acts as an intermediary element that not only mechanically supports the die but also provides electrical interconnection through conductive vias. This intermediary structure enables the transfer of bonding process benefits (signal integrity, cost reduction) to the entire stacked assembly.
2Reliability
If conventional packaging methods are used, then die can be protected and interconnected, but the structures become complex and scalability is limited
Solution Approach 1:
The patent extracts the interconnection function from complex external packaging structures and integrates it directly into the substrate through conductive vias. This eliminates the need for elaborate wire bonds, lead frames, and external interconnect structures, simplifying the overall assembly while maintaining protective and interconnective functions.
Solution Approach 2:
The substrate simultaneously performs multiple functions: mechanical support for die, electrical interconnection through conductive vias, and structural integration for stacked assemblies. By merging these functions into a single element, the design achieves simplicity and scalability without sacrificing reliability.
3Strength
If high temperature bonding processes are used, then strong bonds are achieved, but the pitch between bonding sites must be larger
Solution Approach 1:
The patent changes the bonding parameters by introducing ultrasonic vibration as an additional energy mechanism. This allows the bonding process to occur at lower temperatures and pressures while achieving sufficient bond strength, thereby enabling tighter pitch between bonding sites that would be impossible with conventional high-temperature thermocompression bonding alone.
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 enhances signal integrity, reduces manufacturing costs, and allows for lower temperature bonding with tighter pitches, eliminating the need for conventional wire bonding and mold protection, while facilitating scalability and known good die management.
Implementation Method 1
a first mounted die may be used to heat the substrate to facilitate bonding of the second die
Implementation Method 2
Compression forces and/or ultrasonic vibrations with or without heating the second die may then be applied in combination with the heat from the first die to bond the second die
Data Source
AI summary
A system and method for assembling dual-die integrated circuit packages using thermocompression bonding or thermosonic bonding to bond a second die to a substrate opposite a first die bonded to the substrate. The second die is bonded using heat conducted through the first die to the substrate, and optionally through an underfill material. The first and second die are connected such that bumps are connected to common bonding pads on the substrate. Bumps on one of the die extend through openings in the substrate to connect to the common bonding pads. The bonding pads are within the perimeter of the first die.