Composite Probe with Laser-Machined Trenches for High Current
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Solution Overview
Problem
As electronic circuitry advances to smaller scales, maintaining reliable low-resistance electrical contact becomes challenging due to increased current density, micro-weld formation, and the need for precise control of probe scrub motion, while also avoiding damage to fragile low-K dielectric materials and managing over-current conditions that can cause probe deformation.
Innovation Solution
The development of probes with a combination of high-strength materials like tungsten and conductive coatings, along with laser machining techniques to create precise geometries such as trenches and skates, and the use of power/ground probes and signal probes with forced gas cooling to manage current carrying capacity and prevent inelastic deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If probe size and pitch are decreased to match smaller test contacts, then measurement precision is improved, but current density increases causing micro-weld formation and probe damage
Solution Approach 1:
The probe employs a composite structure combining a high-strength core material (such as tungsten or molybdenum) with a highly conductive coating material (such as copper, aluminum, or gold). This composite design allows the probe to maintain mechanical strength and resistance to micro-weld formation while the conductive coating reduces electrical resistance and manages current density at the contact interface.
Solution Approach 2:
The probe applies different material properties to different regions: the core provides mechanical strength and structural integrity throughout the probe body, while the conductive coating is applied specifically at the contact tip region where current density is highest. This localized application of different material qualities optimizes both mechanical and electrical performance without unnecessary weight or complexity.
2Reliability
If scrub motion is increased to reduce contact resistance, then electrical contact quality is improved, but damage to low-K dielectric materials and underlying circuitry increases
Solution Approach 1:
The probe design modifies the physical parameters of the contact interface by using a composite material structure that changes the friction characteristics and contact mechanics. The conductive coating layer provides a lower friction interface that enables effective scrub motion at reduced pressures, while the core material maintains structural integrity. This parameter change allows scrub motion to be effective without exceeding the damage threshold of low-K dielectric materials.
3Reliability
If probe current carrying capacity is increased to handle over-current conditions, then reliability is improved, but probe deformation due to resistive heating increases
Solution Approach 1:
The composite structure of high-strength core material and highly conductive coating material works synergistically to manage thermal effects. The conductive coating minimizes electrical resistance and thus resistive heating at the contact interface, while the high-strength core material has superior thermal conductivity and heat capacity to dissipate and manage the thermal load throughout the probe body, preventing thermal deformation even under over-current conditions.
4Ease of operation
If conventional buckling beam probes are used to provide resilient deflection and scrubbing, then ease of operation is improved, but assembly complexity increases with decreasing scale
Solution Approach 1:
The probe design segments the functional requirements into distinct material components: the core material provides structural support and mechanical properties, while the conductive coating layer provides electrical conductivity and scrubbing functionality. This segmentation of materials and functions simplifies the overall design and assembly process compared to complex mechanical buckling beam structures, especially at decreasing scales where conventional mechanical assemblies become increasingly difficult to manufacture and assemble.
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
This approach enables reliable, high-current carrying capability while minimizing probe damage and maintaining precise control over scrub motion, ensuring effective electrical contact without damaging low-K dielectric materials and preventing inelastic deformation due to over-current conditions.
Implementation Method 1
cutting the probe material to a depth via a laser following a predetermined probe path
Implementation Method 2
the use of power/ground probes and signal probes with forced gas cooling to manage current carrying capacity and prevent inelastic deformation
Data Source
AI summary
The present invention is a probe having a distal end made of one material, a tip and a portion disposed between the distal end and the tip that is a different second material. The probe is laser machined manufactured using a nanosecond or picosecond laser.