Semiconductor Package Interconnect Structure With Nickel-Solder Joints
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Solution Overview
Problem
Current semiconductor packaging technologies face challenges in achieving reliable interconnects due to excessive intermetallic compound formation, leading to joint yield and reliability issues, particularly when using copper materials which result in thick and rough Cu6Sn5 intermetallic compounds.
Innovation Solution
The use of nickel as a material for connection structures and conductive features, along with solder bump structures, minimizes intermetallic compound formation by controlling the thickness of Ni-Sn intermetallic compounds, thereby improving joint reliability and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper materials are used for connection structures and conductive features, then electrical conductivity is improved, but thick and rough Cu6Sn5 intermetallic compounds form leading to joint yield and reliability issues
Solution Approach 1:
The patent changes the material parameter from copper to nickel for connection structures and conductive features. This material substitution fundamentally alters the intermetallic compound formation characteristics, resulting in thinner and more uniform Ni-Sn intermetallic layers compared to the thick and rough Cu6Sn5 layers that form with copper materials.
2Reliability
If nickel is used for connection structures and conductive features, then intermetallic compound formation is minimized improving joint reliability, but electrical conductivity compared to copper may be affected
Solution Approach 1:
The patent converts the lower electrical conductivity of nickel compared to copper into a benefit by utilizing nickel's reduced reactivity with solder materials. This reduced reactivity prevents excessive intermetallic compound formation, thereby improving joint yield and reliability. The material's apparent disadvantage (lower conductivity) becomes advantageous when considering overall joint performance and reliability.
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 the formation of thick intermetallic compounds, enhancing the reliability and yield of semiconductor package joints by using nickel for connection structures and conductive features, which are less reactive, and solder for bump structures.
Implementation Method 1
The use of nickel as a material for connection structures and conductive features, along with solder bump structures, minimizes intermetallic compound formation by controlling the thickness of Ni-Sn intermetallic compounds
Data Source
AI summary
A package structure includes a semiconductor die, a first insulating encapsulant, a plurality of first conductive features, an interconnect structure and bump structures. The semiconductor die includes a plurality of conductive pillars made of a first material. The first insulating encapsulant is encapsulating the semiconductor die. The first conductive features are disposed on the semiconductor die and electrically connected to the conductive pillars. The first conductive features include at least a second material different from the first material. The interconnect structure is disposed on the first conductive features, wherein the interconnect structure includes a plurality of connection structures made of the second material. The bump structures are electrically connecting the first conductive features to the connection structures, wherein the bump structures include a third material different from the first material and the second material.