Semiconductor Die Reactive Bonding for Low-Temperature Interconnects
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor die stacking methods increase package height and introduce signal propagation delays due to bond wires, and high-temperature annealing processes degrade integrated circuit performance.
Innovation Solution
Implement exothermic reactive bonding using epoxy compounds to generate localized thermal energy for conductive component expansion, forming metallurgical bonds at lower temperatures without post-bond annealing, thereby reducing thermal stress on integrated circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If shingle or zig-zag stacking arrangements are used to stack semiconductor dies, then the footprint of the semiconductor package is reduced, but the package height increases and signal propagation delays are introduced due to bond wires
Solution Approach 1:
The patent replaces the mechanical bonding system (bond wires and bump bonds) with a chemical bonding system (direct bonding of conductive pads). This substitution eliminates the need for bond wires that increase package height, while achieving the same electrical connection function through direct pad-to-pad bonding.
Solution Approach 2:
The patent changes the bonding temperature parameter from low temperature (room temperature or slightly elevated) to high temperature (e.g., 400°C or higher) to enable direct bonding of conductive pads. This parameter change allows formation of strong metallic bonds without requiring bond wires, thereby reducing package height while maintaining electrical connectivity.
2Strength
If high temperature post-bond annealing is applied to form metallic bonds between conductive components, then strong electrical connections are achieved, but the electrical characteristics of integrated circuitry are degraded
Solution Approach 1:
The patent applies local quality by concentrating the high temperature bonding process only at the bonding interface between conductive pads, while the integrated circuitry remains at lower temperature. This is achieved through localized heating methods such as flash heating or induction heating that target only the pad regions, preserving the electrical characteristics of the circuitry while forming strong metallic bonds at the interface.
Solution Approach 2:
The patent performs preliminary actions by preparing the conductive pads with specific surface treatments (such as oxide layers or plating) before bonding. This preliminary preparation enables the pads to form strong metallic bonds at lower temperatures or with shorter heating durations, thereby reducing thermal exposure to the integrated circuitry while still achieving the required bond strength.
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 method reduces package height and signal delays while maintaining bond integrity, ensuring efficient interconnect formation without adverse effects on circuit performance.
Implementation Method 1
at least a portion of the first and second epoxy compounds are bonded to each other in response to an exothermic reaction between the first and second epoxy compounds
Implementation Method 2
the conductive materials of the aligned and directly bonded conductive components are heated to a first temperature to expand toward the bonding interface
Data Source
AI summary
Exothermic reactive bonding for semiconductor die assemblies, and associated systems and methods are disclosed. In an embodiment, a semiconductor die includes a dielectric layer having a conductive pad, where at least a portion of a surface of the dielectric layer includes a first epoxy compound. When another semiconductor die including a second epoxy compound (and another conductive pad) is brought in contact with the semiconductor die such that the first and second epoxy compounds can exothermically react, the thermal energy emanating from the exothermic reaction can facilitate bonding between the conductive pads to form interconnects between the two semiconductor dies. In some cases, the thermal energy is sufficient to form the interconnects. In other cases, the thermal energy assists the post bond annealing process to form the interconnects such that the annealing can be carried out at a lower temperature.