Dual-Melting Solder Structures for Microelectronics
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Solution Overview
Problem
Microelectronic devices with low k-value dielectric materials face damage from thermal stresses during manufacture due to insufficient mechanical strength, and existing solutions like stiffeners or geometry changes are not fully effective in reducing damage.
Innovation Solution
The use of solder structures with a first solder ball having a higher melting temperature and a second connecting structure with a lower melting temperature, both encapsulated in a polymer mold structure, allows for reliable electrical connections by maintaining the solder structure's integrity during the dispense and cure process, avoiding reflow and ensuring consistent height for bridging thermal stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solder structures are used to create electrical connections, then electrical connectivity is achieved, but the solder structures may deform or change height during the dispense and cure process due to thermal stresses, compromising connection reliability
Solution Approach 1:
The patent applies parameter changes by selecting solder materials with specific melting temperatures that are lower than the polymer mold's glass transition temperature. This parameter selection ensures the solder remains in a solid, stable state during the dispense and cure process, preventing deformation and maintaining consistent height for reliable electrical connections
Solution Approach 2:
The patent introduces a polymer mold structure as an intermediary that encapsulates the solder structures. This polymer mold acts as a protective mediator that maintains the solder structures' positions and prevents them from deforming under thermal stresses during the manufacturing process
2Ease of manufacture
If the polymer mold structure is formed at elevated temperatures during dispense and cure, then the mold structure is properly formed, but solder structures with low melting points may reflow and deform, compromising connection integrity
Solution Approach 1:
The patent resolves this contradiction by changing the material parameter selection - specifically choosing solder materials whose melting temperatures are deliberately set below the polymer mold's glass transition temperature. This ensures that during the elevated temperature dispense and cure process, the solder remains stable and does not reflow, while the polymer mold still forms properly
Solution Approach 2:
The patent applies beforehand cushioning by selecting solder materials with appropriate melting temperature characteristics prior to the dispense and cure process. This pre-selection of material parameters cushions against the potential harmful effect of thermal exposure, ensuring the solder structures maintain their integrity throughout the manufacturing process
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 the mechanical strength and reliability of electrical connections in microelectronic devices by maintaining the solder structure's height and integrity, reducing damage from thermal stresses and ensuring consistent, high-quality interconnections.
Implementation Method 1
a first solder ball formed from a first solder having a first melting temperature greater than a glass transition temperature of the polymer
Implementation Method 2
a second connecting structure coupling the first solder ball to one or more electrical connection pads, the second connecting structure formed from a second solder having a second melting temperature lower than the first melting temperature
Data Source
AI summary
An electronic device including a solder structure and methods of forming an electrical interconnection are shown. Solder structures are shown including a solder ball formed from a first solder having a first melting temperature, and a connecting structure coupling the solder ball to one or more electrical connection pads, the connecting structure formed from a second solder having a second melting temperature lower than the first melting temperature. Electronic devices are shown including a polymer mold material formed over the solder structures.