Substrate impedance measurement

A system for testing impedance of a package substrate using time domain reflectometry, the system comprising:

• a time domain reflectometry test station electrically connected to a probe structure, and
• the probe structure having,
• a connector for electrically connecting the probe structure to a time domain reflectometry tester, the connector having a signal conductor and a ground conductor,
• an electrically conductive cantilever signal pin electrically connected to the signal conductor, the electrically conductive cantilever signal pin having a tip for making an electrical connection with an electrically conductive structure to be tested on the package substrate, the electrically conductive cantilever signal pin electrically isolated by and sheathed within a ground shield that is electrically connected to at least one of the ground conductor and electrically conductive cantilever ground pins, and
• the electrically conductive cantilever ground pins electrically connected to the ground conductor, the electrically conductive cantilever ground pins having tips for making electrical connections with electrically conductive structures on the package substrate that surround the electrically conductive structure to be tested on the package substrate.

A system for testing impedance of a package substrate using time domain reflectometry, the system comprising:

• a time domain reflectometry test station electrically connected to a probe structure,
• the probe structure having,
• a connector for electrically connecting the probe structure to a time domain reflectometry tester, the connector having a signal conductor and a ground conductor,
• an electrically conductive cantilever signal pin electrically connected to the signal conductor, the electrically conductive cantilever signal pin having a tip for making an electrical connection with an electrically conductive structure to be tested on the package substrate, the electrically conductive cantilever signal pin electrically isolated by and sheathed within a ground shield that is electrically connected to at least one of the ground conductor and electrically conductive cantilever ground pins, and
• the electrically conductive cantilever ground pins electrically connected to the ground conductor, the electrically conductive cantilever ground pins having tips for making electrical connections with electrically conductive structures on the package substrate that surround the electrically conductive structure to be tested on the package substrate,
• an XYZ stage for moving the package substrate under the probe structure and thereby enabling the automated testing of multiple electrically conductive structures on the package substrate, and
• a pattern recognition system for aligning the electrically conductive pins to the electrically conductive structures on the package substrate.