Interconnection Element Using Low Melting Point Metal Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing interconnection methods for electronic circuit components face challenges in achieving high impact resistance and efficient bump formation, particularly when using nickel layers, which require additional etching processes that can damage terminals and wirings, and are difficult to join with copper foil.
Innovation Solution
The use of a low melting point (LMP) metal layer as a foundation for bumps, which serves as both an etching stop layer and a joining layer, allowing for the formation of bumps with high mechanical strength and reliability, and simplifying the joining process by using metals like tin or tin alloys with a melting point lower than conventional conductors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a nickel layer is used to protect terminals from etching damage, then terminal protection is improved, but device complexity increases due to additional etching processes required
Solution Approach 1:
The patent removes the nickel layer from the structure entirely, replacing it with a copper foil-based bump formation process. This extraction eliminates the need for separate nickel etching processes while still achieving terminal protection through the copper bump structure itself, thereby reducing device complexity while maintaining reliability
Solution Approach 2:
The copper foil serves multiple functions: it forms the bump structure, provides electrical connection, and protects terminals during the etching process. By making the copper foil multi-functional, the patent eliminates the need for separate nickel protection layers and their associated etching processes, reducing overall process complexity while maintaining terminal protection
2Reliability
If a nickel layer is used between copper foil and substrate, then etching damage to terminals is prevented, but manufacturing difficulty increases due to joining challenges
Solution Approach 1:
The patent extracts the nickel layer from the structure, relying solely on copper foil to form bumps that provide both electrical connection and etching protection. This eliminates the manufacturing challenges associated with joining nickel to copper and substrate, while maintaining etching protection through the copper bump structure
Solution Approach 2:
The patent uses copper foil throughout the bump formation process, creating a homogeneous material structure. This eliminates the need to join dissimilar materials (nickel to copper, nickel to substrate), significantly simplifying the manufacturing process while maintaining etching protection functionality
3Reliability
If nickel is used for bump formation, then terminal protection is achieved, but impact resistance is reduced due to difficult joining processes
Solution Approach 1:
The patent removes the nickel layer that creates joining difficulties, using copper foil alone for bump formation. This eliminates the weak interfaces between nickel and copper or substrate, thereby improving impact resistance while maintaining terminal protection through the copper bump structure
Solution Approach 2:
The patent creates a composite structure where copper foil bumps provide both mechanical strength for impact resistance and electrical connection functionality. The copper material properties inherently provide both terminal protection and high impact resistance, eliminating the need for nickel while achieving both goals simultaneously
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 reduces damage to bumps and terminals during the etching process, enhances mechanical strength, and facilitates easy joining of bumps to terminals, improving the mounting density and reliability of electronic circuit connections.
Implementation Method 1
a low melting point (LMP) metal layer having a first face joined to the respective ones of the conductors and bounded in the second direction by at least one edge and a second face joined to the bumps, the edges of the bumps and the LMP layer being aligned in the first direction
Implementation Method 2
The LMP metal in the context of the disclosed embodiments generally refers to a metal having a melting point which is sufficiently low to make it possible to form electric connection by melting
Implementation Method 3
The low melting point (LMP) metal layer has a melting temperature substantially lower than the conductors
Data Source
AI summary
An interconnection element and method for making same is disclosed. The interconnection element may include a plurality of metal conductors, a plurality of solid metal bumps and a low melting point (LMP) metal layer. The solid metal bumps overly and project in a first direction away from respective ones of the conductors. Each bump has at least one edge bounding the bump in at least a second direction transverse to the first direction. The low melting point (LMP) metal layer has a first face joined to the respective ones of the conductors and bounded in the second direction by at least one edge and a second face joined to the bumps. The edges of the bumps and the LMP layer are aligned in the first direction, and the LMP metal layer has a melting temperature substantially lower than the conductors.