Vertical Probe Card Cantilevered Tip with Hardened Alloy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As electronic devices miniaturize, establishing reliable contact with small test pads becomes increasingly difficult due to contamination and oxidation, leading to unstable contact resistance and inefficient testing processes.
Innovation Solution
The design of vertical probe cards is enhanced with a shortened, reinforced cantilevered probe and an elongated axe-head shaped tip coated with a hardening surface alloy, providing improved stiffness and abrupt tearing force to break through contaminants and establish clean metal contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional probe designs are used, then device miniaturization is possible, but contact resistance becomes unstable and testing reliability deteriorates
Solution Approach 1:
The probe structure is divided into different sections with different thicknesses: a thicker base portion for structural support and a thinner contact portion for precise contact and breaking through contaminants. This local variation in geometry optimizes both the mechanical strength needed for miniaturized devices and the contact quality for stable electrical connection.
Solution Approach 2:
The probe incorporates a surface alloy coating on the contact tip, combining the base metal properties with surface hardening and contamination resistance. This composite structure enables the probe to effectively pierce through oxidation layers and debris while maintaining stable electrical contact, solving the reliability issue in miniaturized device testing.
2Reliability
If probe thickness is increased to improve contact force, then contact resistance improves, but probe stiffness and ability to break through contaminants deteriorates
Solution Approach 1:
The probe features a non-uniform thickness distribution with a thicker base for structural integrity and a thinner contact tip for high stress concentration during contaminant breakthrough. This local quality variation allows the probe to maintain both sufficient contact force and the ability to pierce through oxidation and debris effectively.
Solution Approach 2:
The probe geometry parameters are optimized with specific thickness ratios and cantilever dimensions that balance flexibility and strength. The surface alloy coating also changes the material parameters at the contact tip, increasing hardness and enabling effective contaminant breakthrough while maintaining stable electrical contact.
3Ease of operation
If cantilevered portion is elongated to reach small test pads, then accessibility to DUT improves, but probe stiffness and contact stability deteriorates
Solution Approach 1:
The cantilevered portion has varying thickness along its length, being thicker near the base for stiffness and thinner near the contact tip for flexibility and reach. This gradient structure allows the probe to extend to small test pads while maintaining sufficient stiffness for stable contact.
Solution Approach 2:
The surface alloy coating on the contact tip provides enhanced hardness and wear resistance, compensating for the reduced stiffness from the elongated cantilever design. This composite material approach enables the probe to maintain contact stability even with extended reach for accessibility.
Data Source
AI summary
A probe for a vertical probe card includes an unsupported base portion that extends from the vertical probe card, a cantilevered portion that extends substantially perpendicular to the unsupported base portion and a contact portion that includes a tip. The cantilevered portion has a first thickness at an end adjacent the unsupported base portion and a second thickness at an end adjacent the contact portion, the second thickness being less than the first thickness.