Ag-Pd-Cu Probe Pin Alloy for Low Resistance and Bending Strength
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Solution Overview
Problem
Conventional probe pin materials, particularly Ag—Pd—Cu-based alloys, face challenges in achieving a balance of low resistance, high hardness, and sufficient bending resistance, especially when exposed to high temperatures, leading to potential fatigue fractures and reduced performance in high-temperature inspection environments.
Innovation Solution
A Ag—Pd—Cu-based alloy with optimized compositions of Ag, Pd, and Cu, incorporating B as a first additive element and at least one of Zn, Bi, and Sn as a second additive element, within specific concentration ranges, to enhance wear resistance and bending resistance, while maintaining low resistance values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Ag—Pd—Cu-based alloy is used for probe pin material, then low electric resistance is achieved, but wear resistance and bending resistance are insufficient
Solution Approach 1:
The patent creates a composite alloy system by combining Ag—Pd—Cu base alloy with multiple additive elements (Ni, Zn, B, In, Ga, Ge, and/or Pt). This composite approach allows the material to simultaneously achieve low electric resistance from the Ag—Pd—Cu matrix and enhanced wear resistance and bending resistance from the synergistic effects of the additive elements, particularly through the formation of hard intermetallic compounds and optimized phase structures.
Solution Approach 2:
The patent optimizes the concentration ranges of each element in the alloy system. By precisely controlling the composition parameters (Ag: 5-60 mass%, Pd: 5-60 mass%, Cu: 5-60 mass%, and specific ranges for additive elements), the material achieves the optimal balance between electrical conductivity and mechanical properties. The patent also optimizes heat treatment parameters (solution treatment temperature: 600-950°C, aging temperature: 200-500°C) to control phase precipitation and microstructure, thereby enhancing wear resistance and bending resistance while maintaining low resistance.
2Strength
If precious metal base alloy (Pt, Ir, Au) is used for probe pin material, then wear resistance and hardness are improved, but electric resistance increases
Solution Approach 1:
The patent applies local quality by creating a multi-phase microstructure where different regions serve different functions. The Ag—Pd—Cu matrix provides excellent electrical conductivity, while dispersed intermetallic compound particles (formed through controlled precipitation during heat treatment) provide localized wear resistance and hardness. This allows the material to exhibit both low bulk electrical resistance and high surface hardness/wear resistance simultaneously.
3Temperature
If Ag—Pd—Cu-based alloy is exposed to high temperature, then oxidation resistance is needed, but fatigue fracture risk increases
Solution Approach 1:
The patent uses specific additive elements (particularly Ni, Zn, and B) as intermediaries that form protective oxide layers and stabilize the microstructure at high temperatures. These elements act as mediators between the Ag—Pd—Cu matrix and the high-temperature environment, preventing direct oxidation of the base alloy and maintaining structural integrity. The controlled formation of intermetallic compounds also serves as a thermal barrier, reducing thermal stress and preventing fatigue fracture.
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 optimized Ag—Pd—Cu-based alloy exhibits improved specific resistance, hardness, and bending resistance, making it suitable for high-temperature applications and reducing the risk of fatigue fractures, thus enhancing the durability and performance of probe pins in electronic and semiconductor device inspections.
Implementation Method 1
Ag—Pd—Cu alloys are relatively-low-resistance alloys, and furthermore can also be expected to be increased in hardness with PdCu phases formed due to age-precipitation.
Data Source
AI summary
A probe pin material including a Ag—Pd—Cu-based alloy essentially including Ag, Pd and Cu, B as a first additive element, and at least any element of Zn, Bi and Sn, as a second additive element. A concentration of the first additive element is 0.1 mass % or more and 1.5 mass % or less, and a concentration of the second additive element is 0.1 mass % or more and 1.0 mass % or less. A Ag concentration, a Pd concentration and a Cu concentration in the Ag—Pd—Cu-based alloy are required as follows: a Ag concentration (SAg), a Pd concentration (SPd) and a Cu concentration (SCu) converted as given that a Ag—Pd—Cu ternary alloy is formed from only such three elements all fall within a predetermined range in a Ag—Pd—Cu ternary system phase diagram. The probe pin material is excellent in resistance value and hardness/wear resistance, and also is enhanced in bending resistance.