Metal-Post Bump Interconnection to Prevent Solder Bridging
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Solution Overview
Problem
Current semiconductor packaging technologies face challenges in ensuring reliable bump interconnections between semiconductor dies and substrates, particularly due to issues like bridge failures and electrical shorts, which affect the stability and efficiency of semiconductor devices.
Innovation Solution
A method involving the formation of a substrate with connection pads, a solder layer, and a metal post that protrudes from the solder layer, where the substrate is aligned with bump lands on another substrate, and the solder layer is reflowed to interconnect the metal post to the bump lands, thereby reducing the risk of bridge failures and enhancing electrical connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional bump interconnection method is used, then the manufacturing process is simple, but bridge failures and electrical shorts occur frequently
Solution Approach 1:
The bump structure is segmented into three distinct components: a metal post (first conductive layer), a solder layer (second conductive layer), and a barrier layer. This segmentation allows each component to perform its specific function - the metal post provides structural support and initial electrical connection, the solder layer provides reliable bonding, and the barrier layer prevents interdiffusion, thereby improving interconnection reliability while maintaining manufacturing feasibility
Solution Approach 2:
The metal post is formed in advance before the solder layer is applied. This preliminary action ensures that the structural support and alignment features are established before the bonding process, preventing misalignment and reducing the risk of bridge failures during subsequent manufacturing steps
2Strength
If the solder layer is made thicker to ensure reliable bonding, then bonding strength improves, but the risk of bridge failures increases
Solution Approach 1:
The metal post acts as an intermediary element between the substrate and the solder layer. It provides a stable foundation that maintains precise alignment and spacing, allowing the solder layer to bond reliably without excessive thickness that could cause bridging. The barrier layer also serves as an intermediary to prevent interdiffusion between the metal post and solder layer, ensuring long-term reliability
Solution Approach 2:
The invention optimizes the thickness parameters of both the metal post and solder layer to achieve the desired balance. The metal post thickness is controlled to provide sufficient mechanical support while maintaining appropriate spacing, and the solder layer thickness is optimized to ensure bonding strength without creating excessive material that could bridge adjacent bumps
3Manufacturing precision
If a protruding metal post structure is used, then alignment precision improves, but manufacturing complexity increases
Solution Approach 1:
The metal post extends in the vertical dimension (protruding from the substrate surface), creating a three-dimensional structure that provides mechanical alignment features. This dimensional change enables precise alignment during bump formation and assembly processes without requiring complex planar alignment mechanisms, thereby improving manufacturing precision while keeping the process relatively simple
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 reliability and stability of semiconductor device interconnections by minimizing bridge failures and electrical shorts, ensuring robust electrical connectivity and improving the overall performance of semiconductor packages.
Implementation Method 1
reflowing the solder layer to interconnect the metal post to the bump land
Data Source
AI summary
Provided is a method of manufacturing a semiconductor device including a bump interconnect structure. In the method of manufacturing the semiconductor device, a first substrate including a connection pad is formed, and a bump including a solder layer and a metal post protruding from the solder layer are formed on the connection pad. A second substrate including a bump land may be formed. The first substrate may be disposed on the second substrate so that a protruding end of the metal post contacts the bump land, and the solder layer may be reflowed. Accordingly, it possible to interconnect the metal post to the bump land.