Probe Card Inductance Reduction via Interstitial Conductive Regions
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Solution Overview
Problem
In automated test equipment, the long and narrow geometry of vertical probe pins increases inductance between adjacent pins, leading to impedance mismatch during high-frequency signal transmission, causing undesirable signal reflections and loss.
Innovation Solution
The introduction of additional conductive regions between adjacent probe pins, such as short probe pins or protrusions, reduces spacing and inductance, while increasing capacitive coupling, thereby improving impedance matching between probe pins and components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional conductive regions are added between adjacent probe pins, then inductance is reduced and impedance matching is improved, but device complexity increases
Solution Approach 1:
The probe card structure is segmented by introducing additional conductive regions (such as conductive vias or filled holes) between adjacent probe pins. These segmented conductive elements work together to reduce inductance while maintaining a modular structure that can be manufactured using standard PCB techniques.
Solution Approach 2:
Additional conductive regions act as intermediary elements between adjacent probe pins. These intermediate conductive structures provide alternative current paths that reduce the inductance of the probe pin assembly, thereby improving impedance matching without requiring changes to the probe pin geometry itself.
2Reliability
If spacing between probe pins is reduced, then inductance decreases and signal transmission improves, but manufacturing precision requirements increase
Solution Approach 1:
Instead of reducing the horizontal spacing between probe pins (which would increase manufacturing difficulty), the patent introduces additional conductive regions in the vertical dimension (through the substrate thickness). This dimensional approach reduces inductance by providing closer return paths without compromising the horizontal positioning accuracy of the probe pins.
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 solution reduces impedance mismatch and signal loss, ensuring better signal transmission and matching with the components under test, without requiring changes to wafer pad size or spacing.
Implementation Method 1
The introduction of additional conductive regions between adjacent probe pins, such as short probe pins or protrusions, reduces spacing and inductance, while increasing capacitive coupling, thereby improving impedance matching between probe pins and components.
Data Source
AI summary
Probe pin arrangements in a vertical-type probe card assembly for an automated test equipment (ATE) are disclosed. In some embodiments, one or more additional conductive regions are provided in between adjacent probe pins. The additional conductive regions may reduce spacing between probe pins connected to adjacent probe card pads, and may in turn reduce or adjust inductance between the two probe cards pads to provide improved signal impedance matching or lower power impedance. In one embodiment, the additional conductive region is a short probe pin. In another embodiment, the additional conductive region is a protrusion on a vertical probe pin.