Probe Card Probe Chambers for Stress Dispersion in Thin Probes
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Solution Overview
Problem
Existing probes for probe cards face challenges in maintaining mechanical strength while being miniaturized to accommodate smaller semiconductor devices, as they are prone to deformation and stress concentration under external forces.
Innovation Solution
The probes incorporate three-dimensional enclosed stress dispersion chambers with ridges and vertices formed by inner wall surfaces to disperse stress concentration, enhancing mechanical strength and allowing for reduced thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the probe is miniaturized to accommodate smaller semiconductor devices, then the probe can contact smaller electrode pads with reduced pitch, but the mechanical strength of the probe is diminished and it becomes prone to deformation
Solution Approach 1:
The probe is divided into multiple layers (first metallic layer, second metallic layer, third metallic layer) with different materials and properties. Each layer serves specific functions: the first layer provides electrical conductivity, the second layer provides mechanical strength, and the third layer provides wear resistance. This segmentation allows the probe to achieve both miniaturization and sufficient mechanical strength by combining the advantages of different materials in a layered structure.
Solution Approach 2:
The probe employs a composite structure consisting of multiple metallic layers with different material properties. The first metallic layer (e.g., copper or aluminum) provides electrical conductivity, the second metallic layer (e.g., stainless steel or titanium) provides mechanical strength, and the third metallic layer (e.g., diamond-like carbon or tungsten) provides wear resistance. This composite material approach enables the miniaturized probe to maintain adequate mechanical strength while contacting smaller electrode pads.
2Length of moving object
If the probe cross-sectional thickness is reduced to accommodate miniaturization, then the probe can contact smaller electrode pads, but the probe becomes more prone to deformation under external forces
Solution Approach 1:
The probe structure is segmented into multiple functional layers, with the second metallic layer specifically designed to provide mechanical strength and resistance to deformation. This layered segmentation allows the thin-crosssectional probe to maintain structural stability by distributing mechanical stresses across different material layers with optimized properties.
Solution Approach 2:
The composite metallic layer structure enables the probe to achieve adequate resistance to deformation despite reduced cross-sectional thickness. The second metallic layer (e.g., stainless steel or titanium) with high mechanical strength compensates for the reduced overall thickness, while the combination of layers provides both flexibility and structural integrity for reliable contact with miniaturized electrode pads.
3Strength
If the probe surface is smoothed to prevent stress concentration, then the probe can resist destruction under high contact pressure, but there is a limit to how much metal surfaces can be smoothed
Solution Approach 1:
Different regions of the probe are given different surface qualities suited to their specific functions. The contact tip surface is highly smoothed to minimize stress concentration and prevent destruction under high contact pressure, while other portions of the probe can have different surface characteristics. This localized quality optimization achieves the required strength without excessive overall complexity.
Solution Approach 2:
The third metallic layer with wear-resistant and smooth surface properties (e.g., diamond-like carbon coating) is applied specifically to the contact region to prevent stress concentration and destruction. This composite material approach provides the necessary surface quality for resistance to destruction while keeping the overall device complexity manageable by applying specialized surfaces only where needed.
Data Source
AI summary
A probe for a probe card, which is to be placed in contact with electrode pads of a semiconductor device and used for supply of power, input/output of signals, and grounding when performing an operation test of individual semiconductor devices formed on a wafer, includes a plurality of three-dimensionally shaped and enclosed stress-distributing chambers which are embedded inside the probe and have vertices and ridges formed by inner wall surfaces.