Under Barrier Metal Composition for Sn Layer Reliability
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Solution Overview
Problem
The miniaturization of electronic circuits leads to an increase in the proportion of intermetallic compounds at connecting portions between Cu substrates and Sn layers, causing deterioration of electric characteristics and connection reliability, despite the use of Ni plating layers as under barrier metals.
Innovation Solution
A structure incorporating a Sn layer or Sn alloy layer with an under barrier metal formed from single metals like Fe, Co, Ru, Rh, or Pd, or their alloys, which inhibits the formation of intermetallic compounds through metal diffusion, thereby improving electric characteristics and connection reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a Ni plating layer is used as under barrier metal to inhibit intermetallic compound generation, then the connection reliability is improved, but the miniaturization of electronic circuits causes the proportion of intermetallic compound to increase, deteriorating electric characteristics
Solution Approach 1:
The patent changes the material composition parameters of the under barrier metal from conventional Ni plating to specific alloys containing Fe (5-30 mass%), Co (5-30 mass%), and Ni (30-70 mass%). This compositional parameter change enables effective inhibition of intermetallic compound generation even in miniaturized structures, resolving the contradiction between maintaining connection reliability and reducing intermetallic compound proportion.
Solution Approach 2:
The patent employs a composite alloy material for the under barrier metal layer, combining Fe, Co, and Ni in specific proportions. This composite material structure provides superior performance in preventing intermetallic compound formation compared to single-element Ni plating, addressing the issue of increased intermetallic compound proportion in miniaturized circuits while maintaining connection reliability.
2Productivity
If the electronic circuit is miniaturized to improve integration, then the productivity is improved, but the proportion of intermetallic compound in connecting portions increases, causing deterioration of electric characteristics
Solution Approach 1:
By changing the material composition parameters of the under barrier metal to specific Fe-Co-Ni alloy ratios, the patent effectively suppresses intermetallic compound generation in miniaturized structures. This enables continued circuit miniaturization and improved integration density without suffering from increased intermetallic compound proportion that would deteriorate electric characteristics.
3Reliability
If conventional UBM materials like Co plating layer or Ni-Fe alloy plating layer are used, then some inhibition effect is obtained, but it is difficult to sufficiently inhibit generation of intermetallic compound under more severe conditions
Solution Approach 1:
The patent optimizes the compositional parameters of the under barrier metal, specifying Fe (5-30 mass%), Co (5-30 mass%), and Ni (30-70 mass%). This refined parameter range provides superior inhibition capability under severe conditions compared to conventional Co plating or Ni-Fe alloys, sufficiently preventing intermetallic compound generation even when conventional materials fail.
Solution Approach 2:
The patent develops a tri-element composite alloy (Fe-Co-Ni) for the under barrier metal, which provides enhanced performance under severe conditions compared to binary Ni-Fe alloys or pure Co plating. This composite material structure delivers sufficient inhibition of intermetallic compound generation where conventional materials are inadequate.
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
The use of Fe, Co, Ru, or Rh-based under barrier metals significantly reduces the generation of intermetallic compounds, enhancing the electric characteristics and connection reliability of electronic components.
Implementation Method 1
an under barrier metal formed between the substrate and the Sn layer or the Sn alloy layer in the form a single metal layer containing any one of or an alloy layer containing two or more of Fe, Co, Ru, Rh and Pd
Data Source
AI summary
A structure containing a Sn layer or a Sn alloy layer includes a substrate, a Sn layer or Sn alloy layer formed above the substrate, and an under barrier metal formed between the substrate and the Sn layer or Sn alloy layer in the form of a single metal layer containing any one of Fe, Co, Ru and Pd, or an alloy layer containing two or more of Fe, Co, Ru and Pd.