Pd-Cu-Ni Probe Alloy Diffusion Barrier for Solder Inspection
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Solution Overview
Problem
The AgPdCu alloy probe material used for inspecting integrated circuits and liquid crystal display devices experiences rapid tip end consumption due to interdiffusion with solder components under electrical current, leading to varying contact resistance and inspection defects, necessitating frequent cleaning or replacement.
Innovation Solution
A probe material composition of 15-60% Pd, 3-79.9% Cu, and 0.1-75% Ni and/or Pt is developed, which forms a thin intermetallic compound layer at the solder-probe interface to suppress component diffusion, maintaining sufficient hardness and low specific resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If AgPdCu alloy is used as probe material, then low specific resistance and shape stability are achieved, but rapid tip end consumption occurs due to interdiffusion with solder
Solution Approach 1:
The patent introduces Ni and/or Pt as intermediary elements that form a diffusion barrier layer between the probe material and solder. This intermediary layer prevents direct interdiffusion between the AgPdCu probe material and solder components, thereby reducing tip end consumption while maintaining low contact resistance.
Solution Approach 2:
The patent develops a composite alloy material consisting of Ag-Pd-Cu base alloy combined with Ni and/or Pt elements. This composite structure leverages the low specific resistance of AgPdCu while the Ni/Pt components provide solder resistance through formation of protective intermetallic compounds, achieving both low contact resistance and reduced tip end consumption.
2Reliability
If probe material is cleaned or replaced frequently, then inspection defects are reduced, but operating rate is reduced
Solution Approach 1:
The patent applies preliminary action by incorporating Ni and/or Pt elements into the probe material composition before inspection begins. These elements form a protective diffusion barrier layer in advance that prevents solder component interdiffusion during the inspection process, thereby maintaining tip end integrity and reducing the need for frequent cleaning or replacement.
3Reliability
If Ni and/or Pt are added to suppress diffusion, then solder resistance is improved, but material composition complexity increases
Solution Approach 1:
The patent applies parameter changes by optimizing the content ranges of Ni and/or Pt in the alloy composition. By controlling these parameters within specific ranges (0.1-75 mass% for Ni and/or Pt), the patent achieves sufficient solder resistance while avoiding excessive composition complexity. The base AgPdCu alloy maintains its established properties while the Ni/Pt additions provide the necessary diffusion barrier.
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 new probe material effectively prevents solder component diffusion, reducing tip end consumption and maintaining consistent contact resistance, thereby enhancing the operational efficiency of inspection processes.
Implementation Method 1
a probe pin and the solder are repeatedly brought into contact with each other, and an electrical current flows therebetween. As a result, a solder component such as Sn and a component of the probe material interdiffuse due to the resulting Joule heat or the like
Implementation Method 2
a solder component such as Sn and a component of the probe material interdiffuse due to the resulting Joule heat or the like
Data Source
AI summary
Provided is a probe material (an alloy material for probe pins) that can suppress diffusion of components between solder in a circuit connecting portion of an inspection target and the probe material during probe inspection. The alloy material for probe pins consists of 15 mass % to 60 mass % of Pd, 3 mass % to 79.9 mass % of Cu, and 0.1 mass % to 75 mass % of Ni and/or Pt.