Pd-Ag-Ni-Cu Probe Composition to Suppress Solder Diffusion
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Solution Overview
Problem
The diffusion of components between a probe containing a Pd, Ag, and Cu alloy and a solder results in wear and fluctuation of contact resistance, necessitating frequent cleaning and replacement, reducing the operation rate of inspection steps.
Innovation Solution
A probe composition comprising specific mass percentages of Pd, Ag, Ni, and Cu, with optional inclusion of In, Sn, Zn, or Ga, forms a dense thin film that suppresses component diffusion and wear, maintaining contact resistance stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a probe containing Pd, Ag, and Cu alloy is used, then good electrical connection is achieved, but component diffusion occurs between the probe and solder causing wear and contact resistance fluctuation
Solution Approach 1:
The patent introduces an intermediate layer between the Pd-Ag-Cu alloy and the solder. This intermediate layer acts as a diffusion barrier, preventing direct contact and component diffusion between the probe material and solder, thereby maintaining contact resistance stability while preserving good electrical connection properties
Solution Approach 2:
The patent creates a composite structure combining the Pd-Ag-Cu alloy with additional materials that have low diffusion propensity with solder. This composite approach leverages the excellent electrical properties of Pd-Ag-Cu while adding materials that suppress diffusion, thus resolving the contradiction between electrical performance and diffusion resistance
2Productivity
If the distal end of the probe is repeatedly brought into contact with solder, then electrical connection is maintained, but the distal end wears out requiring frequent cleaning or replacement
Solution Approach 1:
The intermediate layer serves as a protective mediator that reduces wear between the probe distal end and solder during repeated contact operations. This protective layer extends probe lifespan while maintaining electrical connection functionality, thereby improving operation rate without sacrificing durability
3Reliability
If alloy components diffuse into solder, then initial connection is established, but contact resistance fluctuates over time
Solution Approach 1:
The intermediate layer acts as a compositional barrier that prevents alloy components from diffusing into the solder. This maintains the stability of both the alloy composition and the solder composition over time, ensuring consistent contact resistance and long-term reliability
Solution Approach 2:
The patent modifies the compositional parameters of the probe structure by adding materials with specific properties (low diffusion propensity with solder). This parameter change in the probe's material composition fundamentally alters the diffusion behavior at the interface, preventing composition instability and contact resistance fluctuation
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 proposed probe composition effectively reduces component diffusion and wear, enhancing the operation rate by stabilizing contact resistance and reducing the need for frequent cleaning or replacement.
Implementation Method 1
The diffusion of the components contained in the probe into a solder can be suppressed
Implementation Method 2
there is a tendency that components such as Sn contained in the solder and components contained in the probe are diffused into each other due to factors such as Joule heat
Data Source
AI summary
A probe including greater than 20 mass % and less than or equal to 60 mass % of Pd, greater than or equal to 3 mass % and less than 20 mass % of Ag, greater than or equal to 3 mass % and less than or equal to 50 mass % of Ni, and greater than or equal to 3 mass % and less than or equal to 74 mass % of Cu.