Redistribution Bond Pad Soldering for Die Alignment and Heat Dissipation
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Solution Overview
Problem
The semiconductor industry faces challenges in miniaturization, alignment issues, and increased thermal resistance in packaging semiconductor dies, particularly in stacked semiconductor devices like 3DICs, where precise alignment and reduced thermal resistance are crucial for efficient performance and reduced manufacturing costs.
Innovation Solution
The method involves forming integrated circuit packages using a die attachment technique that reduces overlay shifts and thermal resistance by attaching integrated circuit dies to bond pads of a redistribution structure via solder joints, which also allows for the formation of through-molding vias directly on the redistribution layer and modifies seed layers to reduce contact resistance, thereby simplifying the manufacturing process and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional die attachment techniques are used in stacked semiconductor devices, then manufacturing process is simpler, but overlay shifts occur and thermal resistance increases
Solution Approach 1:
The redistribution structure is formed with pre-defined bond pads and conductive vias before die attachment. This preliminary structuring enables precise alignment during die stacking by providing fixed reference points, thereby reducing overlay shifts while maintaining manufacturing feasibility through structured process planning
Solution Approach 2:
A redistribution structure serving as an intermediary layer is introduced between stacked dies. This intermediary contains bond pads and conductive vias that facilitate precise electrical and mechanical connection, improving alignment precision while managing the complexity through modular interface design
2Temperature
If conventional packaging techniques are used, then manufacturing cost is lower, but thermal resistance increases
Solution Approach 1:
Conventional mechanical die attachment methods are replaced with solder joint-based attachment. The solder joints provide superior thermal conduction paths compared to traditional adhesive or wire bonding methods, reducing thermal resistance while the standardized soldering process keeps manufacturing costs manageable
Solution Approach 2:
The redistribution structure employs composite material layers including conductive vias, bond pads, and dielectric materials. This composite structure optimizes thermal pathways through strategically placed conductive elements while maintaining electrical isolation, achieving reduced thermal resistance through material composition rather than complex geometry
3Manufacturing precision
If precision alignment is achieved through conventional methods, then overlay shifts are reduced, but contact resistance increases
Solution Approach 1:
The redistribution structure features locally optimized bond pads with enhanced material composition and geometry at critical contact points. These localized enhancements reduce contact resistance specifically at the die-to-substrate interfaces where electrical connection is most critical, while maintaining overall alignment precision through the global structure design
Solution Approach 2:
The bond pad and via dimensions, material composition, and surface treatment parameters are optimized to minimize contact resistance. By adjusting these parameters within manufacturing tolerances, the design achieves both precise alignment and low contact resistance without requiring excessive manufacturing precision
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 effectively reduces thermal resistance, aligns dies accurately, and minimizes contact resistance, leading to more efficient and cost-effective packaging solutions for semiconductor devices, enhancing performance and reducing manufacturing complexity.
Implementation Method 1
heating the solder paste to a melting temperature to form a solder joint
Implementation Method 2
reflowing the solder paste to form the solder joint
Data Source
AI summary
An integrated circuit package and a method of forming the same are provided. A method includes forming a first redistribution layer over a carrier, the first redistribution layer including a contact pad and a bond pad. A conductive pillar is formed over the contact pad. A backside surface of an integrated circuit die is attached to the bond pad using a solder joint. An encapsulant is formed along a sidewall of the conductive pillar and a sidewall of the integrated circuit die, a front-side surface of the integrated circuit die being substantially level with a topmost surface of the encapsulant and a topmost surface of the conductive pillar. A second redistribution layer is formed over the front-side surface of the integrated circuit die, the topmost surface of the encapsulant and the topmost surface of the conductive pillar.