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 the time domain reflectometry tester, the connector having a signal conductor and a ground conductor,
• a layered substrate having,
• a non electrically conductive back side layer physically connected to the connector,
• a non electrically conductive probe side layer with electrically conductive contacts, including a centrally disposed signal electrical contact and surrounding ground electrical contacts,
• an electrically conductive layer disposed between the back side layer and the probe side layer, the electrically conductive layer electrically connected to the ground conductor of the connector, the electrically conductive layer also electrically connected to the ground electrical contacts of the probe side layer electrical contacts, and
• an electrically conductive via extending from the back side layer to the probe side layer, the electrically conductive via electrically connected to the signal conductor of the connector, the electrically conductive via also electrically connected to the centrally disposed signal electrical contact of the probe side layer electrical contacts, and the electrically conductive via not making electrical connection with the electrically conductive layer, and
• electrically conductive pins,
• a first of the electrically conductive pins electrically connected to the signal electrical contact, for making an electrical connection with an electrically conductive structure to be tested on the package substrate, and
• others of the electrically conductive pins electrically connected to the ground electrical contacts, 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 the time domain reflectometry tester, the connector having a signal conductor and a ground conductor,
• a layered substrate having,
• a non electrically conductive back side layer physically connected to the connector,
• a non electrically conductive probe side layer with electrically conductive contacts, including a centrally disposed signal electrical contact and surrounding ground electrical contacts,
• an electrically conductive layer disposed between the back side layer and the probe side layer, the electrically conductive layer electrically connected to the ground conductor of the connector, the electrically conductive layer also electrically connected to the ground electrical contacts of the probe side layer electrical contacts, and
• an electrically conductive via extending from the back side layer to the probe side layer, the electrically conductive via electrically connected to the signal conductor of the connector, the electrically conductive via also electrically connected to the centrally disposed signal electrical contact of the probe side layer electrical contacts, and the electrically conductive via not making electrical connection with the electrically conductive layer, and
• electrically conductive pins,
• a first of the electrically conductive pins electrically connected to the signal electrical contact, for making an electrical connection with an electrically conductive structure to be tested on the package substrate, and
• others of the electrically conductive pins electrically connected to the ground electrical contacts, 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.