Semiconductor Package Interconnect Structure With Nickel-Based 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 reliability concerns and yield issues, particularly when using copper materials which form thick and rough Cu6Sn5 compounds.
Innovation Solution
The use of nickel as a material for connection structures and conductive features, along with a reflow process that controls intermetallic compound thickness, minimizes the formation of intermetallic compounds by using nickel-based materials which are less reactive, 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 intermetallic compound formation increases leading to joint reliability degradation
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 chemical reactivity parameters, preventing excessive intermetallic compound formation while maintaining electrical conductivity. The nickel-based materials exhibit controlled reactivity that eliminates the harmful thick Cu6Sn5 compound formation issue.
Solution Approach 2:
The patent employs nickel-based composite materials or alloys for connection structures and conductive features. These composite materials combine nickel with other elements to optimize both electrical conductivity and intermetallic compound formation control, achieving a balance between electrical performance and joint reliability.
2Ease of manufacture
If copper-based interconnects are used, then manufacturing ease is improved, but intermetallic compound thickness increases causing yield issues
Solution Approach 1:
The patent changes the material parameter from copper to nickel, which fundamentally alters the intermetallic compound formation characteristics. Nickel-based materials produce minimal and controllable intermetallic compound thickness, eliminating the yield issues associated with uncontrolled thick compound formation while remaining manufacturable through standard reflow processes.
3Strength
If reflow process is applied to copper-based interconnects, then bonding is achieved, but intermetallic compound formation increases reducing joint reliability
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 chemical reactivity parameters during reflow, preventing excessive intermetallic compound formation while maintaining bonding strength. The nickel-based materials exhibit controlled reactivity that eliminates the harmful thick Cu6Sn5 compound formation issue.
Solution Approach 2:
The nickel-based materials act as an intermediary between the bump structures and the underlying conductive pillars, providing a stable interface that prevents excessive intermetallic compound formation. The nickel layer mediates the bonding process, allowing strong adhesion while controlling the chemical reactions that occur during reflow.
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 thickness of intermetallic compounds to a minimal range, enhancing the reliability and yield of semiconductor package joints by controlling the formation of nickel-based intermetallic compounds, thus addressing the reliability concerns associated with copper-based interconnects.
Implementation Method 1
a reflow process that controls intermetallic compound thickness, minimizes the formation of intermetallic compounds by using nickel-based materials
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.